Well I got this question:

Differentiate from first principals (i did it)

Find the equation of the normal to the curve at point where x = 3.

So first I found y.

That means we got

Then I subbed 3 into

to get the gradient of the tangent. Answer is

Since the normal and tangent are perpendicular the formula is

So that makes

Then I subbed it into

** <=== you used the wrong sign in the bracket**

Finally I get

but

**for some reason** **<=== maybe they believe that 27² = 729**
the answers in the book says it's different

Did I do anything wrong?

Also, I need help with another question:

If

find the derivative and find the values of y when

How would I go about starting this one?