June 2014 FP2 (R) question 8:
For the second differentiation, they have multiplied the differentiation by dy/dz on both sides. I have no idea why they have done that. My differentiation is the same but without the additional dz/dx on both sides.
Clear image if you don't know what I mean:
I have a fp2 mock tomorrow and this question is killing me!
FP2 Second order Differential Question help! Urgent! Watch
- Thread Starter
- 11-01-2015 17:55
- 11-01-2015 18:08
They have used the product rule, but as you are differentiating with respect to x, and both of the functions have Z's in them, they have differentiated both implicitly
i.e d/dx e^-z = -e^-z(dz/dx) and d/dx(dy/dz) = d^2y/dz^2(dz/dx)