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Activity 5.3.4.
Evaluate each of the following definite integrals exactly through an appropriate
\(u\)-substitution.
(a)
\(\int_1^2 \frac{x}{1 + 4x^2} \, dx\)
(b)
\(\int_0^1 e^{-x} (2e^{-x}+3)^{9} \, dx\)
(c)
\(\int_{2/\pi}^{4/\pi} \frac{\cos\left(\frac{1}{x}\right)}{x^{2}} \,dx\)
