I usually find it easier to do these if I express everything in terms of sinx or cosx.
secx = 1/cosx
cotx = cosx/sinx
tanx = sinx/cosx
cscx = 1/sinx
So, we can rewrite the question as
(cosx/(1/cosx)) - (sinx/(cosx/sinx)) = (cosx*(cosx/sinx)-sinx/cosx)/(1/sinx)
because(x)^2 - sin(x)^2/cosx = (because(x)^2/sinx - sinx/cosx)*sinx (simplify a bit)
because(x)^3 - sin(x)^2 = because(x)^3 - sin(x)^2 (multiply by cosx)
secx = 1/cosx
cotx = cosx/sinx
tanx = sinx/cosx
cscx = 1/sinx
So, we can rewrite the question as
(cosx/(1/cosx)) - (sinx/(cosx/sinx)) = (cosx*(cosx/sinx)-sinx/cosx)/(1/sinx)
because(x)^2 - sin(x)^2/cosx = (because(x)^2/sinx - sinx/cosx)*sinx (simplify a bit)
because(x)^3 - sin(x)^2 = because(x)^3 - sin(x)^2 (multiply by cosx)