## anonymous one year ago guys correct me if im wrong, ∫ cos 3x dx answer: =∫cos(u)1/3 dx cos(u) =∫---- dx 3 =1/3 sin (3x) final answer : = sin(3x) ----- +c 3 correct?

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1. anonymous

wrong or not?

2. anonymous

@campbell_st sir

3. campbell_st

well I know that $\int\limits \cos(ax) ~dx = \frac{1}{a} \sin(ax) + C$ hope that helps

4. campbell_st

5. anonymous

thank you sir!!

6. ganeshie8

One nice way to double check the answer is by simply differentiating the answer you should get back the integrand if your answer is correct

7. anonymous

@campbell_st is right. you've got the correct answer.