5.5 EXERCISES
1-6 Evaluate the integral by making the given substitution:
1. ∫ e^{-x} dx, u = -x
2. ∫ x^3(2 + x^4)^5 dx, u = 2 + x^4
3. ∫ x^2√(x^3 + 1) dx, u = x^3 + 1
4. ∫ dt / (1 - 6t)^4, u = 1 - 6t
5. ∫ cos^3 ̈θ sin θ dθ, u = cos θ
6. ∫ sec^2(1/x) / x^2 dx, u = 1/x