# Calculus - find dy/dt thank you

1. Apr 6, 2005

### laker_gurl3

calculus -.. find dy/dt...thank you..:(

can someone plz help me out with this question...i did it all sorts of way,quotient rule, product rule..etc.. but i can never match the answer in the book..i just wanna know if u did..

find dy/dt = x^2 Tanx / sec x

The answer in the book was
x(xcosx + 2sinx)

lemmi know how you did it with a couple steps! thanks soo mcuh

2. Apr 6, 2005

### Data

Do you mean find

$$\frac{d}{dx} \frac{x^2 \tan{x}}{\sec{x}}$$

?

If so, here:

$$\frac{x^2 \tan{x}}{\sec{x}} = x^2\tan{x}\cos{x} = x^2 \frac{\sin{x}}{\cos{x}}\cos{x} = x^2 \sin{x}$$

I'm sure you can take the derivative from there~

3. Apr 6, 2005

### Nylex

Damn you Data!

4. Apr 6, 2005

### Data

got to be quick :tongue: