是算错了来的

1. ∫kdx = kx + C (k 是常数)
2. ∫xdx = (x^2)/2 + C
3. ∫dx = ln|x| + C
4. ∫1/xdx = ln|x| + C
5. ∫a^xdx = a^x/lna + C
6. ∫e^xdx = e^x + C
7. ∫sinxdx = -cosx + C
8. ∫cosxdx = sinx + C
9. ∫1/(cosx)^2dx = tanx + C
10. ∫1/(sinx)^2dx = -cotx + C
11. ∫secxdx = ln | secx + tanx | +C
12. ∫cscxdx = cotx + C
13. ∫f'(x)dx = f(x)
14. ∫d(f(x)) = f(x) + C
15. ∫1/(a^2 - x^2) dx = (1/2a) *ln|(a + x)/(a - x)| + C
16. ∫1/(a^2 + x^2) dx = (1/a) *arctan(x/a) + C
17. ∫1/√(a^2 - x^2) dx =arcsin(x/a) + C
18. ∫sec^2 x dx = tanx + C
19. ∫shx dx = chx + C
20. ∫chx dx = shx + C
21. ∫thx dx = ln(chx) + C
22. 令 u = 1/x, 即 du = -1/x^2 dx
百度的，我记得∫dx = ln|x| + C，是变换成 ∫1dx = ln|x| + C 这个X必须是正数，