∫ from 0 to π/2 sin x cos x dx =
Aπ/2
B1/2 (use sin x cos x = sin 2x / 2)
C0
D1
Answer & Solution
Correct answer: B. 1/2 (use sin x cos x = sin 2x / 2)
sin x cos x = sin(2x)/2. ∫₀^(π/2) sin(2x)/2 dx = -cos(2x)/4 from 0 to π/2 = -cos π/4 - (-cos 0/4) = 1/4 + 1/4 = 1/2. (Or by sub u = sin x.)
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