Calculating 3-Variable Derivative: Solving for dz/dt with x^2 + 3xt + 2t^2 = 1

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SUMMARY

The discussion focuses on calculating the derivative dz/dt for the function z = (x^2)(t^2) under the constraint x^2 + 3xt + 2t^2 = 1. The solution involves implicit differentiation, where the first equation is differentiated with respect to t, yielding dz/dt = 2tx^2 + 2t^2x(dx/dt). The second equation is also differentiated, resulting in (2x + 3t)(dx/dt) = -(3x + 4t), which allows for the substitution of dx/dt in the first equation to find dz/dt.

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Homework Statement



Find dz/dt where z = (x^2)(t^2) and x^2 + 3xt + 2t^2 = 1.

2. The attempt at a solution

I really have no idea how to go about this, I've tried rearranging the second expression in terms of x but it's no help.
 
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Use the impllicit differentiation.

Differentiating the first equation, with respect to t,
[tex]dz/dt= 2tx^2+ 2t^2x dx/dt[/tex]

Differentiating the second equation, with respect to t,
[tex]2x dx/dt+ 3t dx/dt+ 3x+ 4t= 0[/tex]
so
[tex](2x+ 3t)dx/dt= -(3x+ 4t)[/tex]
and
[tex]dx/dt= -(3x+4t)/(2x+ 3t)[/tex]
Replace dx/dt in the first equation by that.
 

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