12)ed=e2+C (13)a' dx=lna +c(a>0,a+1) (14) tan xdx=-In x|+C 15) cot xdx=In sinx|+C (16) secxdx=In secx+tanx +C (17) csc xdx=In cscx-cotx +Ce dx e C x x = +  (12) C a a a dx x x = +  ln (13) (a >0, a  1) xdx = − x +C  (14) tan ln | cos | xdx = x +C  (15) cot ln |sin | xdx = x + x +C  (16) sec ln |sec tan | xdx = x − x +C  (17) csc ln | csc cot |