How can I simplify numerical calculations in symbolic math toolbox?
조회 수: 3 (최근 30일)
이전 댓글 표시
Hi there,
When I write this:
fR == simplify((Alpha/uR)*((y/uR)^(Alpha-1))*exp(-(uS/y)^k))
I get something like this:
fR =
(12153*exp(-(10/y)^(601/100))*(y/20)^(11153/1000))/20000
Could you tell me please how to simplify the numerical calculations?! I mean I want the term "(11153/1000))/20000" be printed as "0.000557".
Thanks
댓글 수: 0
채택된 답변
Star Strider
2015년 10월 16일
Use the vpa function. (If you want to solve an equation and avoid fractions, use the vpasolve function.)
댓글 수: 3
Star Strider
2015년 10월 16일
Actually, that’s essentially what you want. It’s just expressing the decimal fractions literally instead of as decimals. However, I’m not quite certain why it’s rendering, for instance, (11153/1000) as a fraction and not as 11.153. Maybe close enough is good enough for vpa. (I get the same result as you do.)
Walter Roberson
2015년 10월 16일
Exponents are not converted to floating point because a floating point exponent means something different than a rational exponent. With rational exponents you need to worry about multiple roots and principle roots, but with floating point exponent the operation x^(a/b) is defined strictly in terms of exp(a/b * log(x)) which is a single value that is complex in cases where algebraic x^(a/b) might be real-valued.
추가 답변 (0개)
참고 항목
카테고리
Help Center 및 File Exchange에서 Assumptions에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!