Problem : f (x) = 2x. Find f'(x)
Problem :
Find the slope of the line perpendicular to the tangent of the graph of f (x) = - x2
at x = 1.
f'(1) = - 2.
This is the slope of the tangent. The perpendicular to the tangent has a slope that is the negative
reciprocal of this, which is
.
Problem :
Give an example of a function that is not differentiable at x = a.
f (x) =|x - a| is not differentiable at
x = a because
it has a corner there.