can you please add answer 4 for completeness?

[ihadanny]

Forecasting_with_R_practices/Chapter5.rmd

Line 565 in 0f884ec

### Question 4, 8 are related with math, not related with coding that I didn't include them in here.

We take the derivative with respect to x from both sides of the equation:

log(y(x)) = b0 + b1log(x) + eps
dy/dx * 1/y(x) = 0 + b1/x + 0 (we assume that eps is independent of x)
b1 = x/y(x) * dy/dx