\(\int_0^{\pi / 2} e^{\sin x} \cdot \cos x d x=\)

\(\int_0^{\pi / 2} e^{\sin x} \cdot \cos x d x=\)
  1. \(1-e\)
  2. \(1+e\)
  3. \(e-1\)
  4. \(e\)

Solution

\(I=\int_0^{\pi / 2} e^{\sin x} \cos x d x\) Put \(\sin x=t\), then at \(x=0, t=0\) and at \(x=\frac{\pi}{2}, t=1\) and \(\cos x d x=d t\) So, \(I=\int_0^1 e^t d t=\left[e^t\right]_0^1=e^1-1=e-1\)

Asked in: AP EAMCET 2020 (18 Sep Shift 1)

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