How do you integrate cosx sin2x?

  • Thread starter Thread starter IntegrateMe
  • Start date Start date
  • Tags Tags
    Integrate
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
2 replies · 3K views
IntegrateMe
Messages
214
Reaction score
1
If dy/dx = cosx sin2x and if y = 1 when x = pi/2, what is the value of y when x = 0?

So, i separate the derivative into dy = cosx sin2x dx

Then integrate both sides...this is where I'm stuck.

How do you integrate cosx sin2x? I've tried u-sub and IBP but failed both times!
 
Physics news on Phys.org


[tex]\int cosxsin^2x dx[/tex]

u = sinx
du = cosx dx

[tex]\int u^2 du[/tex]

= [tex]\frac{u^3}{3}[/tex]

= [tex]\frac{sinx}{3}[/tex]

plugging in 0 for x gets me [tex]\frac{1}{3}[/tex]

Correct?

CORRECTION: Nevermind, i got it. They gave me an initial condition.
 
Last edited: