Solve the below:
Q: Verify each differentiation formula and explain how.
(a) d/dx[arctan u] = u'/1 + u^2
(b) d/dx[arcsec u] = u'/lul (square root of u^2 -1)
(c) d/dx[arccos u] = -u'/square root of 1 - u^2
(d) d/dx[arccot u] = -u'/1- u^2
(e) d/dx[arccsc u] = -u'/lul (square root of u^2 - 1