Evaluate the integral by making the given substitution. (Use C for the constant of integration.) sin3 (θ) cos (θ) dθ, u = sin (θ) g

Evaluate int[sin^3 (θ) cos (θ) dθ] with u = sin (θ)

du/dθ = cos (θ), dθ = du/cos (θ)

The integral becomes:

int[u^3•cos (θ) du/cos (θ) ]

= int[u^3•du]

= u^4/4 + C

Substitute u = sin (θ) to get back a function of θ:

sin^4 (θ) / 4 + C