derivatives
posted by sara .
find the derivative of
y=2cotx+sec3x+cscX
find d^2/dx^2 for 1+y=x+xy

The derivatives of these trig functions should be right there in your Calculus text.
for the second of your questions, I will use y' for the first derivative and y" for the second derivative i.e. y'= dy/dx
1+y=x+xy so
y' = 1 + y + xy'
y'(1x) = 1+y
y' = (1+y)/(1x)
y" = [(1x)y'  (1+y)(1)]/((1x)^2)
=[(1+y) + (1+y)]/((1x)^2) after I replaced y'
=(2+2y)/((1x)^2)