a curve in the plane is defined parametrically by the equations x = t^3 - 6t and y = sqrt(2 - t^2). find…

a curve in the plane is defined parametrically by the equations x = t^3 - 6t and y = sqrt(2 - t^2). find dy/dx. choose 1 answer: a -t/((3t^2 - 6)(sqrt(2 - t^2))) b (6 - 3t^2)(sqrt(2 - t^2)) c (6 - 3t^2)/sqrt(2 - t^2) d -t/sqrt(2 - t^2)
Answer
Answer:
A. $-\frac{t}{(3t^{2}-6)(\sqrt{2 - t^{2}})}$
Explanation:
Step1: Differentiate $x$ with respect to $t$
$\frac{dx}{dt}=\frac{d}{dt}(t^{3}-6t)=3t^{2}-6$
Step2: Differentiate $y$ with respect to $t$
Using the chain - rule, if $y = \sqrt{2 - t^{2}}=(2 - t^{2})^{\frac{1}{2}}$, then $\frac{dy}{dt}=\frac{1}{2}(2 - t^{2})^{-\frac{1}{2}}\cdot(-2t)=-\frac{t}{\sqrt{2 - t^{2}}}$
Step3: Use the formula $\frac{dy}{dx}=\frac{\frac{dy}{dt}}{\frac{dx}{dt}}$
$\frac{dy}{dx}=\frac{-\frac{t}{\sqrt{2 - t^{2}}}}{3t^{2}-6}=-\frac{t}{(3t^{2}-6)\sqrt{2 - t^{2}}}$