ok, here's a tough one:

as x approaches pi/6, evaluate the limit of (cos(2x) - .5)/(x-pi/6)

My first thought was to treat it like a derivative. I basically tried subbing h for (x-pi/6), and then since f(x) is -1/2, assuming that the piece on top should be cos(pi/6 + h) - cos(pi/6). So if that's the case, then shouldnt the limit be approaching 1 as h approaches 0? I feel as if I have made a grave error somewhere in that substitution process...

Question

ok, here's a tough one:

as x approaches pi/6, evaluate the limit of (cos(2x) - .5)/(x-pi/6)

My first thought was to treat it like a derivative. I basically tried subbing h for (x-pi/6), and then since f(x) is -1/2, assuming that the piece on top should be cos(pi/6 + h) - cos(pi/6). So if that's the case, then shouldnt the limit be approaching 1 as h approaches 0? I feel as if I have made a grave error somewhere in that substitution process...

anonymous · Answer

anyone know how to do this?