Logarithmic Function Problem?

0 ⤊

Logarithmic Function Problem?

This is a two part problem that I am not sure on. The question is:
f(x)=2ln(8x)

Find
f'(x)=
f'(5)=

Any help would be great!

2007-05-06 19:02:33 · 3 answers · asked by Mark S 1 in Science & Mathematics ➔ Mathematics

3 answers

Let y = 2 ln (8x)
let u = 8x
du/dx = 8
y = 2 ln u
dy/du = 2 / u = 2 / 8x = 1 / 4x
dy/dx = dy/du X du/dx
dy/dx = 1 / (4x) X 8
dy / dx = 2 / x
f ` (x) = 2 / x
f ` (5) = 2 / 5

2007-05-07 00:10:59 · answer #1 · answered by Como 7 · 0⤊ 0⤋

First differentiate 2ln(8x) = ??/?. Then assign x=5.

2007-05-07 02:08:00 · answer #2 · answered by singlepun 3 · 0⤊ 0⤋

f(x)= 2Ln(8x)
F'(x)= 2*(1/8x)*8 ===== 1/gx*g'x
F'(x)= 2/x
F'(x)= 2/5

2007-05-07 02:34:59 · answer #3 · answered by frizzball2me 1 · 0⤊ 0⤋