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

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