So what else ?
i got it but cannot understand how you got rid of the -cosx+sinx
the answer doesnt equal (sinx-cosx)^2... from that last step, how did you get from -cosx(sinx-cosx) etc to:
(sinx-cosx)+(sinx-cosx)? i mean where did the -cosx before the bracket go to? as well as the +sinx before the bracket?