Question: how do you find the slope of a line tangent to a circle?
Answer: slope of a line tangent to the top half of the circle. To compute this derivative, we first convert the square root into a fractional exponent so that we can use the rule from the previous example. dy 1 dx = 2 u−1/2 · (-2x) = -x · (1 - x 2)−1/2 = / 1 - - x x2 .