# Derivative

• Oct 22nd 2007, 02:19 PM
ocmisssunshine
Derivative
The given limit is a derivative, but of what function f(x) and at what point.

limit as change of x approaches 0 of the (tan(pi/4+change of x)-1)/ change of x.

• Oct 22nd 2007, 02:22 PM
Jhevon
Quote:

Originally Posted by ocmisssunshine
The given limit is a derivative, but of what function f(x) and at what point.

limit as change of x approaches 0 of the (tan(pi/4+change of x)-1)/ change of x.

the function is f(x) = tan(x), and we are considering the derivative at the point x = pi/4

is that what you wanted?
• Oct 22nd 2007, 02:26 PM
galactus
$\lim_{h\rightarrow{0}}\frac{tan(\frac{\pi}{4}+h))-1}{h}$

What is $tan(x)$ when $x=\frac{\pi}{4}$?.
• Oct 22nd 2007, 02:27 PM
ocmisssunshine
No I have to find what function F(x) and at what point from the limit which is a derivative. which is the tan(pi/4+deltax)-1 all divided by delta x
• Oct 22nd 2007, 02:30 PM
ocmisssunshine
the tangent of pi/4 is one
• Oct 22nd 2007, 02:32 PM
galactus
Yes. That's what I am getting at. See the 1 in your limit?. The function you wish to find is in front of you.
• Oct 22nd 2007, 02:35 PM
ocmisssunshine
omg I look over the obvious all the time. Thank you so much!! I always make things more complicated then they have to be.