Q. If 4x+y2+2−y3=−2x2 then find dxdy at the point (−4,3)Answer: dxdy∣∣(−4,3)=
Differentiate Equation: First, we need to find the derivative of the given equation with respect to x to find dxdy. The given equation is 4x+y2+2−y3=−2x2. We will differentiate each term with respect to x, treating y as a function of x (implicit differentiation).
Differentiate 4x: Differentiate 4x with respect to x. The derivative of 4x with respect to x is 4.
Differentiate y2: Differentiate y2 with respect to x. Since y is a function of x, we use the chain rule: the derivative of y2 with respect to x is 2y(dxdy).
Differentiate 2: Differentiate 2 with respect to x. The derivative of a constant is 0.
Differentiate −y3: Differentiate −y3 with respect to x. Again using the chain rule, the derivative of −y3 with respect to x is −3y2dxdy.
Differentiate −2x2: Differentiate −2x2 with respect to x. The derivative of −2x2 with respect to x is −4x.
Combine Differentiated Terms: Combine all the differentiated terms to form the derivative of the entire equation: 4+2ydxdy−3y2dxdy=−4x.
Isolate dxdy: Now we need to solve for dxdy. We can rearrange the terms to isolate dxdy on one side of the equation: 2ydxdy−3y2dxdy=−4x−4.
Factor Out (dxdy): Factor out (dxdy) from the left side of the equation: (dxdy)(2y−3y2)=−4x−4.
Solve for (dxdy): Divide both sides by (2y−3y2) to solve for (dxdy):(dxdy)=2y−3y2−4x−4.
Substitute Point: Now we substitute the point (−4,3) into the equation to find the value of (dxdy) at that point: (dxdy)∣(−4,3)=2(3)−3(3)2−4(−4)−4.
Calculate Numerator: Calculate the numerator: −4(−4)−4=16−4=12.
Calculate Denominator: Calculate the denominator: 2(3)−3(3)2=6−3(9)=6−27=−21.
Divide Numerator by Denominator: Now, divide the numerator by the denominator to find (dy/dx) at the point (−4,3): (dy/dx)∣(−4,3)=−2112.
Simplify Fraction: Simplify the fraction−2112 to get the final value of (dy/dx) at the point (−4,3): (dy/dx)∣(−4,3)=7−4.
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