just needed a clue on how to start the math behind this thanks!!
find a unit vector, if terminal point is at (4,4) on 4y=x^2, is normal to the curve and pointed towards the positive y-axis
I hope that I understand your question correctly this time ..
Here are the steps to perform:
1. Determine the gradient m of the curve at P(4, 4).
2. Determine the orthogonal direction n of the gradient using $\displaystyle m\cdot n = -1$
3. n can be written as a vector $\displaystyle \vec n = (1, n)$. Determine the length of $\displaystyle \vec n$ and consequently
4. Calculate the unit vector of $\displaystyle \vec n$