find the derivative of ln(x^2)-3y=2-3x(lny) I know this is an implicit differentiation, and have gotten as far as: dy/dx=((lny)(-3)-(2x/x^2))/(-3+(3x/y)) My friend and I have been working on it for over an hour. If someone could please give a step by step answer, we would appreciate it so much!!
let's do this term by term \[\frac{d}{dx}\ln(x^2)=2 \frac{d}{dx} \ln(x)=?\]
Here is a more clear representation of what we have \[\frac{ dy }{ dx }= \frac{ (lny)(-3)-(\frac{ 2x }{ x^2 }) }{ -3+(\frac{ 3x }{ y }) }\]
\[\frac{ dy }{ dx }(lnx^2)=\frac{ 1 }{ x }(2x)\]
well actually it would be 2x/x^2
or just 2/x
derivative of inside/inside
right, that is what I meant, but I forgot to add the ^2
\[\frac{d}{dx}(-3y)= -3 \frac{d}{dx}y=-3 \frac{dy}{dx}=-3y' \\ \frac{d}{dx}(2)=0 \\ \frac{d}{dx}[-3x \ln(y)]=-3 \frac{d}{dx}x \ln(y) \text{ here we need product rule }\]
Just to clarify, I'm not having a problem getting there, we understand implicit differentiation. It's simplifying the answer we already have as we cannot have complex fractions or negative exponents
\[\frac{2}{x}-3y'=0-3[\ln(y)+x \frac{y'}{y}]\]
you need to get your y' 's on one side
correct, we already took the derivative and put them on one side. that is what the dy/dx is. the y that is still in the equation is from the derivative of lny
\[\frac{2}{x}+3\ln(y)=-3x \frac{y'}{y}+3y'\]
\[\frac{2}{x}+3 \ln(y)=y'(\frac{-3x}{y}+3)\] here I would write both the left hand side as one term by combing the fractions and the thing inside the ( ) on the right hand side as one fraction
then divide both sides by whatever y' is being multiplied by
then get rid of the complex fraction by multiplying bottom and top by the lcm's of their bottoms if you know what I mean
\[\frac{2+3x \ln(y)}{x}=y'(\frac{-3x+3y}{y}) \]
or you could just multiply both sides by the thing that is next to the y' 's reciprocal
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