Q.Find
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Start your 14-day free trial to unlock the full solution →Both integrals use the reverse product rule — the idea that . For (i) we identify ; for (ii) we rewrite the integrand to match the pattern with .
The Core Idea: Why Integrals Are Special
When you see multiplied by a sum of a function and its derivative, you’re looking at a disguised derivative of . Check:
So if your integrand is , the antiderivative is simply . This is the reverse product rule — no integration by parts needed.
Part (i):
1. Spot the pattern.
We have times something. Look at the bracket: .
Recall that . So the bracket is exactly with .
2. Apply the formula directly.
Since , the antiderivative is .
No integration by parts, no substitution — just pattern recognition. If you see and a sum that looks like “function + its derivative”, you’re done. …
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