# Answer to Question #20125 in Real Analysis for RUTH

Question #20125

If y=-2x^(3)-3x, determine dy/dt when x=1 and dx/dt=4

dy/dt=?

dy/dt=?

Expert's answer

Here we differentiated bothparts of equation, knowing that f(x(t))'=f'(x(t))*x'(t), then we simply put the

values of x and x'(t) into the obtained expression:

dy/dt=-6x^2(dx/dt)-3dx/dt=-24-12=-36

values of x and x'(t) into the obtained expression:

dy/dt=-6x^2(dx/dt)-3dx/dt=-24-12=-36

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