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TS EAMCET · Maths · Indefinite Integration

If \(\int \mathrm{e}^x\left(\sin ^2 2 \mathrm{x}-8 \cos 4 \mathrm{x}\right) \mathrm{dx}=\mathrm{e}^x f(\mathrm{x})+\mathrm{c}\), then \(f\left(\frac{\pi}{4}\right)=\)

  1. A \(0\)
  2. B \(1\)
  3. C \(-1\)
  4. D \(e\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(1\)

Step-by-step Solution

Detailed explanation

\begin{aligned} & \int e^x\left(\sin ^2 2 x-8 \cos 4 x\right) d x \\ & =\int e^x\left(\frac{1-\cos 4 x}{2}-8 \cos 4 x\right) d x \\ & =\int e^x\left(\frac{1-17 \cos 4 x}{2}\right) d x \\ & =\frac{1}{2}\left[\int e^x d x-17 \int e^x \cos 4 x d x\right] \\ & \because \int e^{a x}…