hey all i'm having alot of bother with these two questions. any comments would be very much appreciated!!!

1)

show that the derivative of

arctan(a + x/1 -ax) is independent of a and explain why

2)

use the substitution x-p = 1/u to show the integral of

1/(x-p)sqrt((x-p)(x-q)) = 2/(q-p) . sqrt((x-q)/(x-p))

thanks muchly!!!!!