Homework Help: Calculus(f(x)= tan(2x)

1. Mar 17, 2010

SAT2400

1. The problem statement, all variables and given/known data

If f(x)= tan(2x), then f'(pi/6) =

2. Relevant equations

deriv. of tan(pi/3)

3. The attempt at a solution

How can I solve this? I am not supposed to use a calculator?? tan(pi/3) ...am I supposed to memorize this?

2. Mar 17, 2010

Pinu7

What is f'(x) ?
Hint: use the chain rule.

3. Mar 17, 2010

SAT2400

tan(pi/3) ' = sec^2(pi/3) is it??

4. Mar 17, 2010

jav

And now how can you simplify that using the definition of sec?

5. Mar 18, 2010

Staff: Mentor

The derivative of tan(pi/3) is zero. tan(pi/3) is a constant, and the derivative of any constant is zero.
Yes. There are a few angles whose trig functions you should have memorized - 0, pi/6, pi/4, pi/3, pi/2, as well as their supplements and combinations with pi/2, pi, and so on. You should also have memorized all of the six trig functions in terms of the sine or cosine.

6. Mar 18, 2010

Pinu7

Can you write sec x in terms of sine and/or cosine? You should have memorized the values of sin(pi/3) and cos(pi/3)