Integrate: ∫ sin3 x cos2x dx
Dear student,
Given that, ∫ sin3 x cos2x dx
This can be written as:
∫ sin3 x cos2x dx = ∫ sin2 x cos2x (sin x) dx
=∫(1 – cos2x ) cos2x (sin x) dx —(1)
Now, substitute t = cos x,
Then dt = -sin x dx
Now, equation can be written as:
Thus, ∫ sin3 x cos2x dx = – ∫ (1-t2)t2 dt
Now, multiply t2 inside the bracket, we get
= – ∫ (t2-t4) dt
Now, integrate the above function:
= – [(t3/3) – (t5/5)] + C —(2)
Where C is a constant
Now, substitute t = cos x in (2)
= -(⅓)cos3x +(1/5)cos5x + C
Hence, ∫ sin3 x cos2x dx = -(⅓)cos3x +(1/5)cos5x + C
Regards