Question

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?

Answer 1

wrong or not?

Answer 2

@campbell_st sir

Answer 3

well I know that

\[\int\limits \cos(ax) ~dx = \frac{1}{a} \sin(ax) + C\]

hope that helps

Answer 4

so your answer looks correct

Answer 5

thank you sir!!

Answer 6

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

Answer 7

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