Implicit differentitaion and finding coordinates

AI Thread Summary
To find the x-coordinates where the tangent line is vertical for the curve defined by the equation x(y^2) - (x^3)y = 6, the denominator of the derivative dy/dx must be set to zero. This leads to the conditions x = 0 and 2y = x^2. By substituting these values back into the original equation, one can solve for the corresponding y-values. The process involves using the zero product property to simplify the equations. Ultimately, this method allows for the determination of the points on the curve where the tangent line is vertical.
brambleberry
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Homework Statement



dy/dx = [3(x^2)y - y^2] / [2xy - x^3]

Find the x-coordinate of each point on the curve where the tangent line is vertical.

Homework Equations



original equation is x(y^2) - (x^3)y = 6

The Attempt at a Solution



i set the denominator of the deriv. to 0, but i have no idea where to go from there. am i solving for x or y? is there a way i can eliminate one of the variables? do i need to plug anything into the orig. equation?
 
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You have two equations and two variables so it shouldn't be difficult to get what you need. Setting the denominator to zero, you can solve for y. Then using the original equation, you can solve for x.
 
snipez90 said:
You have two equations and two variables so it shouldn't be difficult to get what you need. Setting the denominator to zero, you can solve for y. Then using the original equation, you can solve for x.

i don't know how to solve for y using the equation x(y^2) - (x^3)y = 6...i get stuck
 
Try this: the denominator equals x(2y - x^2), therefore, using the zero product property, the denominator is equal to zero when x = 0 and 2y = x^2. Use the second equation with the original to determine which values of x and y work.
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
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