Before we move to the next topic, I want you to see that the breadcrumb trail exactly matches [code]f'(x)=2x+2[/code]. To that end, I've zoomed way in.[br][br]Adjust [code]A[/code] along [code]f(x)[/code], and convince yourself that the function [code]f'(x)=2*x+2[/code] exactly encodes the slopes of the tangent lines of [code]f(x)[/code].

Move on after you've had a close look.