# How do you find the unit vector, in the first quadrant, that is parallel to the line tangent to the parabola y = x^2 at the point (4, 16)?

##### 1 Answer

Jul 6, 2016

(1/sqrt 65, 8/sqrt 65)

#### Explanation:

The slope of the tangent

So, the principal value of

And so,

For the opposite direction,

be < 0... .

The unit vector for inclination

The unit vector in this direction could be anywhere in the plane.

The reference to first quadrant, for its presence, is not necessary..