1. ## Exponentials and logarithims

I get as far as dy/dx= -3e^-3x +2, then making this equal to zero, then going blank

2. Originally Posted by gamboo

I get as far as dy/dx= -3e^-3x +2, then making this equal to zero, then going blank
$\displaystyle 0 = -3e^{-3x} +2 \Rightarrow \frac{2}{3} = e^{-3x} \Rightarrow \ln \frac{2}{3} = -3x \Rightarrow x = -\frac{1}{3} \ln \frac{2}{3}$.

Substitute into $\displaystyle y = e^{-3x} + 2x$ and simplify to get the given value of y.