# Math Help - Please Check: Itergrate by Substitution

1. ## Please Check: Itergrate by Substitution

Q. Use as substitution to find:

{Intergration symbol} sin(3 + 2x) . dx

if U = 2x + 3 then du = 2. dx

= 1/2 {Intergration symbol} sin (U) . du

= - cos (U) / 2 + c

= - 1/2 . cos (2x + 3) + c

Not sure the method is correct?

2. Originally Posted by Parton-Bill
Q. Use as substitution to find:

{Intergration symbol} sin(3 + 2x) . dx

if U = 2x + 3 then du = 2. dx

= 1/2 {Intergration symbol} sin (U) . du

= - cos (U) / 2 + c

= - 1/2 . cos (2x + 3) + c

Not sure the method is correct?
Perfectly done. You are correct.

3. Originally Posted by Parton-Bill
Q. Use as substitution to find:

{Intergration symbol} sin(3 + 2x) . dx

if U = 2x + 3 then du = 2. dx

= 1/2 {Intergration symbol} sin (U) . du

= - cos (U) / 2 + c

= - 1/2 . cos (2x + 3) + c

Not sure the method is correct?
Best way to check is find $\frac{d}{dx}\left(\frac{- 1}{2} \cos (2x + 3) + C\right)$