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The value of ∫0 dx / [(a2 + x2)] is

1) π/2 2) π/2a 3) π/a 4) 1/2a Solution: (2) π/2a \(\begin{array}{l}\int_{0}^{\infty} \frac{d x}{a^{2}+x^{2}}\\=\frac{1}{a}\left[\tan ^{-1} \frac{x}{a}\right]_{0}^{\infty} \\ =\frac{1}{a}\left[\frac{\pi}{2}-0\right]\\=\frac{\pi}{2 a}\end{array} \)

0π/2 |cos (x / 2)| dx =

1) 1 2) -2 3) √2 4) 0 Solution: (3) √2 \(\begin{array}{l}\int_{0}^{\frac{\pi}{2}}\left|\cos \frac{x}{2}\right| d x \\=\int_{0}^{\frac{\pi}{2}}\left|\cos \frac{x}{2}\right| d x \\... View Article