Title: Derivative Questions - Solutions Post by: slimes on Feb 5, 2021 Can someone confirm if these answers are correct? Thanks
a) y = 8x lim h->0 f(x + h) - f(x)/h lim h->0 8(x + h) - 8x/h <- Distribute the 8(x +h) lim h->0 8x + 8h - 8x/h <- Cancel out 8x and -8x lim h->0 8h/h <- Cancel h's lim h->0 = 8 b) 3x^2 - 2x lim h->0 f(x + h) - f(x)/h lim h->0 3(x + h)^2 - 2(x + h) - (3x^2 - 2x)/h <- Distribute -2(x + h) and -(3x^2 - 2x) lim h-> 3x^2 + 6xh + 3h^2 - 2x - 2h - 3x^2 + 2x/h <- Cancel out lim h->0 3h^2 + 6xh - 2h/h = h(3h + 6x - 2)/h <- Cancel out lim h->0 3h + 6x - 2 lim h->0 dy/dx = 6x - 2 c) (2x - 1)^2 -> (2x - 1)(2x - 1) = 4x^2 - 4x +1 lim h-> 0 f(x + h) - f(x)/h lim h->0 4(x + h)^2 - 4(x + h) + 1 - (4x^2 - 4x + 1)/h <- Distribute lim h->0 4x^2 + 8xh + 4h^2 - 4x - 4h + 1 - 4x^2 + 4x - 1/h lim h->0 4h^2 + 8xh - 4h/h = 4h(h + 2x -1)/h ,- Cancel out + Distribute the 4 = dy/dx 8x-4 Title: Re: Derivative Questions - Solutions Post by: bio_man on Feb 5, 2021 All of these are correct 👍 👍
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