Integrating sin(2x) in MATLAB

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Shane Yost
Shane Yost on 8 Jul 2013
Introduction:
I'm new to MATLAB and trying to learn how to integrate expressions.
Situation:
The expression to integrate is.....
sin(2x)
I'm entering the following code......
syms x
int(sin(2*x))
The answer MATLAB is displaying is.....
ans =
sin(x)^2
The answer I'm looking for is....... (-1/2)*cos(2x)+c

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 9 Jul 2013
syms x
out = feval(symengine,'combine',int(sin(2*x)),'sincos')

More Answers (1)

Azzi Abdelmalek
Azzi Abdelmalek on 9 Jul 2013
(-1/2)*cos(2x)=(-1/2)*(cos^2(x)-sin^2(x))
=(-1/2)*(1-sin^2(x)-sin^2(x))
=(-1/2)+sin^2(x)
=sin^2(x)+c
The result found by Matlab and yours are the same
  1 Comment
Jan
Jan on 9 Jul 2013
@Shane Yost: Interesting, isn't it? Matlab replied the correct result, but you've expected another correct result.

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