00:01
For this problem, our function is f of x equals a x squared plus bx plus c.
00:05
So we want to take the limit, or actually let me write it this way, we'll have that f prime of x, prime of x, will be equal to the limit.
00:16
So h approaches zero of, now it would be a times x plus h squared, which becomes a x squared, plus two a x h plus two h squared, or excuse me, 2, not 2, excuse me, that should just be plus a times h squared.
00:35
Then we'd have plus b times x plus h, expanding that out, that becomes bx plus bh, plus c, and then we want minus f of x.
00:45
So we have minus a x squared, minus bx, minus c, and that is all getting divided by h...