# Thread: derivative help before im off to bed

1. ## derivative help before im off to bed

Have an exam and need help with these 2 before im off to bed, im not sure where to start so if someone could help me in the right direction id appreciate it. Thanks :]

and

2. im in the library at school, still cant figure these two out...anyone here can lead me to the right direction? gracias :]

3. Use chain rule and differentiate it with respect to theta.

4. Originally Posted by tecknics
Have an exam and need help with these 2 before im off to bed, im not sure where to start so if someone could help me in the right direction id appreciate it. Thanks :]

You can first write ln(e^w/(8+e^w)) = ln e^w - ln(8+e^w) =
w - ln(8+e^w) , with w = theta, and the derivative of this is:

1 - e^w/(8+e^w) = 8/(8+e^w)

and

Differentiate implicity: (1/y)dy + (1/x)dx = e^(x+y)dy + e^(x+y)dx ==>

[1/y - e^(x+y)]dy = -[1/x - e^(x+y)]/dx...etc.

Tonio

5. Thanks i got it now:] just needed to be steered to the right direction