Thread: Derivatives: Logarithmic Differentiation

So i solved a few of the steps but i'm stuck at this one step and can't move on

Find y if

y=(10x+9)^10x+1


Note: The product of two numbers or two expressions should be entered as a*b. For the quotient of two numbers use a/b. For the power use a^b.

1. Take the natural logarithm of both sides:
lny = ln (10*x+9)^(10*x+1)

2. Simplify by using properties of logarithms:
Important! In your answer, lna must be entered as log(a).
lny = (10*x+1)*log(10*x+9)

3. Differentiate both sides with respect to x:
yy = (Help please)

4. Solve for y:
y = y( )

5. Substitute the original expression for y to get y in terms of x only:
y =


If someone could help me from 3 onwards i would really appreciate it.

Thanks

can't you use

then

Ah that was it, thanks a lot!