You end up with -(1/sqrt2)/0 limit. the equation is an identity that is supposed to help when solving the question.
I also tried expanding the relevant equation and ended up with, cos(2x)+cos(2a)=-2sin(x+a)sin(x-a)
Homework Statement
Find the limit as x approaches ∏/8, (cos(2x)-√(2))/(x-∏/8)Homework Equations
cos(2x)+cos(2a)The Attempt at a Solution
I tried to multiply the conjugate of the terms but ended up stuck there, don't know how to go on. Please help.