Hey,

I am looking to antiderive the following:

$\displaystyle \int (3-sin{3x})(cos{3x})dx$

Any help is much appreciated,

Dranalion

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- Oct 10th 2009, 02:18 AMDranalionIntegral
Hey,

I am looking to antiderive the following:

$\displaystyle \int (3-sin{3x})(cos{3x})dx$

Any help is much appreciated,

Dranalion - Oct 10th 2009, 03:42 AMgalactus
$\displaystyle \int (3-sin(3x))cos(3x)dx$

Just make the sub $\displaystyle u=sin(3x), \;\ \frac{du}{3}=cos(3x)dx$

Now, it should be easier.

$\displaystyle \frac{1}{3}\int (3-u)du$ - Oct 10th 2009, 03:50 AMDranalion
Using this, does this give the answer:

= sin(3x) - 1/6(sin^2(3x)) + c ?

I am just checking to see if I followed it correctly. - Oct 10th 2009, 04:17 AMmr fantastic
- Oct 10th 2009, 04:19 AMDefunkt