L'hopital

[Jaina]

I'm supposed to use L'Hopital's rule to find this:

lim x->(π/4) of -(x-(π/2))tanx

(I don't know if you can tell but that funky π symbol is supposed to be pi)

Here's what I've done so far:

lim x->(π/4) of -((2x-π)/2)tanx
lim x->(π/4) of ((π-2x)/2)tanx
lim x->(π/4) of ((π-2x)tanx)/2

Which presents a problem because the bottom of the fraction isn't 0 or infinity, and if I take the derivative of it I end up with 0. What am I missing?

 

[tkhunny]

It is possible that you are missing the correct problem statement.

L'Hopital's Rule applies to Indeterminate Forms. You don't have an indeterminate form around pi/4. tan(pi/4) = 1