# Homework Help: Derivative of a trig function

1. Sep 28, 2007

### fitz_calc

real quick review needed, I'm working through the quotient rule on a problem and need the first derivative of:

(1+tanx)

is it simply equal to:

(0 + sec^2x * 1)
(sec^2 x)

??

2. Sep 28, 2007

### rocomath

yes that's correct

1 = 0, $$\tan{x}=\sec^2{x}$$

3. Sep 28, 2007

### CompuChip

Geez, that's a nice identity.
I wish I could use that on my exam, it would make life a lot easier

4. Sep 28, 2007

### rocomath

lol, you know what i meant ;)

5. Sep 28, 2007

### CompuChip

Yeah, I know you meant

1' = 0, $$\tan(x)' = \sec^2(x)$$
where $$' = \frac{\rm d}{{\rm d}x}$$.