Question

integrate 6θcosθdθ by using integration by parts with u = 6θ, dv = cosθdθ

Answer 1

formula : int (u dv) = uv - int (v du)

Answer 2

let u = 6θ ---> du = ... ?
dv = cosθ dθ ----> v = int cosθdθ = ... ?
do u know that ?

Answer 3

Yeah I got 6θsinθ-int(6θcosθ)dθ

Answer 4

then i got 6θsinθ-3θ^2sinθ .... Is that correct or do i did i do my integration wrong?

Answer 5

u = 6θ ---> du =6 dθ

dv = cosθ dθ ----> v = int cosθdθ = sinθ
formula : uv - int (v du)
= 6θsinθ - int(6sinθ ) dθ
= 6θsinθ - (-6cosθ) + c (remember that integral of sinx = -cosx)
= 6θsinθ + 6 cosθ + c

Answer 6

Thank you! I had my formula written down wrong!!

Answer 7

welcome

Answer 8

My answer is still incorrect

Answer 9

oh well

Answer 10

the god of MATH told me, my answer was right ;)
http://www.wolframalpha.com/input/?i=int%286%CE%B8cos%28%CE%B8%29%29d%CE%B8+++

Answer 11

i know but i typed it on webassign and it says it is wrong.

Answer 12

do u have options of the answer ?