\fThe Substitution Rule for Definite Integrals: If g' is continuous on [a, b] and f is continuous on the range of u = g(x), then [ f(8(8' (x)dx = [ flu)du z(a) 9. Evaluate the definite integral in two ways. [V 4 + 3x dx . 10. Evaluate [ xcos(x] ) dx. 1/2 11. Evaluate cscatcot at di 1/6x sin x x sin x 12. dx [Hint: What kind of a function is ?] 1+x 1+x -x/2