Using the fact that "ln ( u(x)/v(x) )= ln u(x)−ln v(x),
use the chain rule and the formula for the derivative of ln x to derive the quotient rule. That is, find the derivative of [u(x)/v(x)] without using the quotient rule.
PLZ HELP THIS QUESTION ...
Do I have to use the ln fact? u(x)/v(x) is like saying u(x) times v(x)-1. For simplicity, I'll use u for u(x) and v for v(x) Now use the product rule:
d/dx [u * v-1]
d/dx [u] * v-1 + u * d/dx [v-1] Use chain rule
u' * v-1 + u * (-1)(v)-2 * v'
u'/v - uv'/v2 Multiply u'/v by v to combine into a single denominator and:
(u'v - uv')/v2
So:
d/dx [u/v] = (u'v - uv')/v2
Do I have to use the ln fact? u(x)/v(x) is like saying u(x) times v(x)-1. For simplicity, I'll use u for u(x) and v for v(x) Now use the product rule:
d/dx [u * v-1]
d/dx [u] * v-1 + u * d/dx [v-1] Use chain rule
u' * v-1 + u * (-1)(v)-2 * v'
u'/v - uv'/v2 Multiply u'/v by v to combine into a single denominator and:
(u'v - uv')/v2
So:
d/dx [u/v] = (u'v - uv')/v2
Using the fact that "ln ( u(x)/v(x) )= ln u(x)−ln v(x),
use the chain rule and the formula for the derivative of ln x to derive the quotient rule. That is, find the derivative of [u(x)/v(x)] without using the quotient rule.
Thanks HamboneJoe,
Here is an alternate answer using the given fact.
letu=u(x),v=v(x),dudx=u′,dvdx=v′ lnuv=lnu−lnvelnuv=e(lnu−lnv)uv=e(lnu−lnv)ddxuv=ddx(lnu−lnv)∗e(lnu−lnv)ddxuv=(u′u−v′v)∗eln(uv)ddxuv=vu′−uv′uv∗uvddxuv=vu′−uv′v2