13 2 arctan +c (a>0) a x dx= arcsin -+c(a>0) 2 15. secxdx= In tan x+secx+C 16. csc xdx=-Incotx +cscx+C atx 17. In +c 2 2 2 - 2021/2/202021/2/20 7 arctan ( 0) 1 1 13. 2 2 = +  +  C a a x a dx a x arcsin ( 0) 1 14. 2 2 = +  −  C a a x dx a x 15.  secxdx = ln tan x + secx +C 16.  csc xdx = −ln cot x + csc x +C C a x a x a dx a x + − + = −  ln 2 1 1 17. 2 2