How to use a for loop to solve a function?

Not sure where I'm going wrong. While loop works correctly, but not sure what's happening with the for loop.

x=linspace(0,20,20);

a=0;

while(a<=20)

y=x.^6-(3.*x).^2+3.^x-(230.*x);

a=a+1;

end

for j=1:20

y2(j)=100.*3log(j)-(2.*j);

end

When plotting, the while loop plots how it should, but nothing shows up for the for loop. Any guidance welcome. Thank you!

Answer 1

[Ameer Hamza]

In your code, the while loop has no use. I think you wanted to write it like this

while(a<=20)
    y(a)=x(a).^6-(3.*x(a)).^2+3.^x(a)-(230.*x(a));
    a=a+1;
end

The for loop seems fine except there is a typing error. Following should work fine and you can plot the output

for j=1:20
    y2(j)=100.*3*log(j)-(2.*j);
end

[Jer D]

Sorry for the confusion. The while loop was used to solve for one function, and the for loop is for another function. I'm trying to get them to plot on one graph however, only the while loop is graphing which made me assume that my for loop isn't working. For some reason, the for loop won't graph at all.

[Ameer Hamza]

They are both visible, but y2 have very small values as compared to y, so it is on lower part axes (see the orange line on x-axes

x=linspace(0,20,20);
a=1;

while(a<=20)
    y(a) = x(a).^6-(3.*x(a)).^2+3.^x(a)-(230.*x(a));
    a=a+1;
end

for j=1:20
    y2(j) = 100.*3*log(j)-(2.*j);
end

f = figure();
hold on;
plot(y);
plot(y2);