Hey guys check this out, we have to diffrentiate this:

y = tan inverse of ( (1+x)^2 + (1-x)^2/(1+x)^2 - (1-x)^2

If we assume x = sin@, then the answer comes out to be smth +ve
but if we assume x = cos@ then the answer comes out to be -ve, numerically being the same as the previous result. Why is there such a sign difference based on substitution? Will it cause problems in future problems????