gaokao 2017 Q20

gaokao · China · national-I-arts 12 marks Tangents, normals and gradients Find tangent line equation at a given point
(12 points)
Let $A$ and $B$ be two points on the curve $C: y = \frac{x^2}{4}$, and the sum of the $x$-coordinates of $A$ and $B$ is 4.
(1) Find the slope of line $AB$;
(2) Find the equation of line $AB$.
(12 points)

Let $A$ and $B$ be two points on the curve $C: y = \frac{x^2}{4}$, and the sum of the $x$-coordinates of $A$ and $B$ is 4.

(1) Find the slope of line $AB$;

(2) Find the equation of line $AB$.