Question

Determine an expression, in simplified form, for the slope of the secant PQ.


Given: P(1,3) , Q(1+h, f(1+h)) , where f(x) = 3x^2

PQ=Y2-Y1/X2-X1

I keep getting wrong answer, arghhh.

Answer 1

f(1+h) = 2(1+h)^2 = 3(1 + 2h + h^2)
= 3 + 6h + 3h^2
f(1) = 3

slope of secant = (3 + 6h - 3h^2 - 3)/(1+h - 1)
= (6h - 3h^2)/h
= 6 - 3h