How to find the inverse of a function numerically

조회 수: 81 (최근 30일)
BeeTiaw
BeeTiaw 2019년 1월 28일
댓글: BeeTiaw 2019년 1월 28일
Hi expert,
Can someone tell me how is it possible to find the inverse of this function
in which z is a complex number and cannot be zero. , a and b are constant.
How to solve this function for ?
Data (Example)
The following is obtained using the following input:
for
theta=[
0
0.6981
1.3963
2.0944
2.7925
3.4907
4.1888
4.8869
5.5851
6.2832];
The results is:
z = [
2.9400 + 0.0000i
3.2277 + 2.1618i
2.2730 + 1.2986i
0.4557 - 2.2605i
-1.4094 - 6.6606i
-2.3950 - 9.7020i
-1.9857 -10.1025i
-0.4083 - 7.8642i
1.5321 - 3.9596i
2.9400 - 0.0000i
];
Example:
I used Matlab function "roots" to solve the following inversion problem
by rearrange the function into:
and use to function "roots" to find the solution.
  댓글 수: 9
BeeTiaw
BeeTiaw 2019년 1월 28일
Torsten, the original question does not allow me to make such matrix.
How do I suppose to transform the following matrix into polynomial so that I can use "roots"?
Or, am I missing your point here?
BeeTiaw
BeeTiaw 2019년 1월 28일
Oh probably I can do it by multiplying them with

댓글을 달려면 로그인하십시오.

채택된 답변

John D'Errico
John D'Errico 2019년 1월 28일
Multiply by zeta^2, and collect terms. As long as zeta is not zero, that is not a problem. Your equation reduces to
b*m2 + (a + b*m1)*zeta - z*zeta^2 + (a*m1 + b)*zeta^3 + (a*m2)*zeta^4 == 0
We only need to worry about zeta==0 if either of b or m2 was zero. In that case, zeta==0 would be one of the roots of the above equation.
Of the coefficients of the above equation, all are apparently known, and have fixed values. So there are 4 roots.
Then the "inverse" is given as any of the 4 roots of that equation, thus:
zetaroots = solve(b*m2 + (a + b*m1)*zeta - z*zeta^2 + (a*m1 + b)*zeta^3 + (a*m2)*zeta^4,zeta,'maxdegree',4);
You don't want me to write the entire expression in here, as it is a massive mess of terms.
The problem is, the "inverse" is a rather nasty mess of a function of z. There are 4 solutions. Even if I show only 5 digit numbers in that expression for all coefficients, it is still a nasty mess.
vpa(expand(subs(zetaroots,{a,b,m1,m2},[-2.0800,4.0800,0.5,-0.03])),5)
ans =
- (0.16667*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))/(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6) - (0.16667*(10680.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 70.15*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 256.82*z^2*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) + 2868.6*z*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) + 106211.0*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) + 192.31*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))^(1/2))/((0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/4)) - 12.179
(0.16667*(10680.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 70.15*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 256.82*z^2*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) + 2868.6*z*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) + 106211.0*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) + 192.31*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))^(1/2))/((0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/4)) - (0.16667*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))/(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6) - 12.179
(0.16667*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))/(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6) - (0.16667*(10680.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 70.15*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 256.82*z^2*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 2868.6*z*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) - 106211.0*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) + 192.31*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))^(1/2))/((0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/4)) - 12.179
(0.16667*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))/(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6) + (0.16667*(10680.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 70.15*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 256.82*z^2*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2) - 2868.6*z*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) - 106211.0*(5.1962*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 6767.6*z - 8231.4*z^3 - 125699.0)^(1/2) + 192.31*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/2))^(1/2))/((0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/6)*(96.154*z*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 5340.2*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(1/3) + 9.0*(0.096225*(2.07e6*z^4 + 7.6638e7*z^3 + 1.1346e6*z^2 + 6.3008e7*z + 5.8506e8)^(1/2) - 125.33*z - 152.43*z^3 - 2327.6)^(2/3) + 256.82*z^2 + 70.15)^(1/4)) - 12.179
I'm not at all sure what you expected the inverse of your function would look like. But it is not pretty.
  댓글 수: 2
BeeTiaw
BeeTiaw 2019년 1월 28일
Hi, thanks!
I have posted another question related to this post which consider a much more generalised form of function. How do we determine the solution?
BeeTiaw
BeeTiaw 2019년 1월 28일
An answer for a much more generalised form of function is available here https://uk.mathworks.com/matlabcentral/answers/441867-tthe-inverse-of-a-function-numerically-with-n-terms

댓글을 달려면 로그인하십시오.

추가 답변 (0개)

카테고리

Help CenterFile Exchange에서 Logical에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by