Q. Let y be defined implicitly by the equation(−8x−2y)3=−x2−10y2.Use implicit differentiation to find dxdy.
Differentiate with respect to x: Differentiate both sides of the equation with respect to x. We have the equation (−8x−2y)3=−x2−10y2. We will apply the chain rule to the left side and the power rule to the right side. Remember that when differentiating y with respect to x, we treat y as a function of x and use the chain rule to include dxdy.
Apply chain rule to left side: Apply the chain rule to the left side of the equation.The derivative of (−8x−2y)3 with respect to x is 3∗(−8x−2y)2∗(−8−2∗dxdy), where we have multiplied by the derivative of the inside function (−8x−2y), which is −8 for the x part and −2∗dxdy for the y part because y is a function of x.
Apply power rule to right side: Apply the power rule and chain rule to the right side of the equation.The derivative of −x2 with respect to x is −2x, and the derivative of −10y2 with respect to x is −20ydxdy, where we have multiplied by dxdy because y is a function of x.
Write down differentiated equation: Write down the differentiated equation.We now have 3(−8x−2y)2(−8−2dxdy)=−2x−20ydxdy.
Solve for dxdy: Solve for dxdy.To solve for dxdy, we need to collect all terms containing dxdy on one side and the rest on the other side. We get:3(−8x−2y)2(−2dxdy)−20ydxdy=−2x−3(−8x−2y)2(−8).
Factor out dxdy: Factor out dxdy from the left side of the equation.dxdy×(3(−8x−2y)2(−2)−20y)=−2x−3(−8x−2y)2(−8).
Simplify expression for dxdy: Simplify the expression for dxdy if possible.We can leave the expression as it is because it does not simplify easily. So, the final answer is:dxdy=−6(−8x−2y)2−20y−2x+3⋅8(−8x−2y)2.
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