A curve has equation y f x a Write an expression for the slope of the secant line through the points P 2 f 2 and Q x f x O 2 2 f x X f x f 2 X 2 X 2 f x f 2 f x X f 2 2 b Write an expression for the slope of the tangent line at P X 2 X 2 f x f 2 Olim lim X 2 f x f 2 X 2 O lim f x f 2 lim X40 X 2 x 0 2 2