Q. If −y2=x2−x+3y3 then find dxdy at the point (−4,−2).Answer: dxdy∣∣(−4,−2)=
Differentiate Left Side: First, we need to differentiate both sides of the equation with respect to x to find dxdy. The equation is −y2=x2−x+3y3. We will use implicit differentiation because y is a function of x.
Differentiate Right Side: Differentiate the left side of the equation with respect to x: dxd(−y2)=−2y⋅dxdy.
Equate Derivatives: Differentiate the right side of the equation with respect to x: dxd(x2−x+3y3)=2x−1+3×3y2×dxdy because we need to use the chain rule for the term 3y3.
Rearrange Equation: Now we equate the derivatives from the left and right sides: −2y⋅(dxdy)=2x−1+9y2⋅(dxdy).
Isolate dxdy: Rearrange the equation to solve for dxdy: (dxdy)⋅(9y2+2y)=2x−1.
Calculate Numerator: Now we substitute the point (−4,−2) into the equation to find the value of dxdy at that point: (dxdy)∣(−4,−2)=(9∗(−2)2+2∗(−2))(2∗(−4)−1).
Calculate Denominator: Calculate the numerator: 2×(−4)−1=−8−1=−9.
Divide Numerator: Calculate the denominator: 9∗(−2)2+2∗(−2)=9∗4−4=36−4=32.
Divide Numerator: Calculate the denominator: 9(−2)2+2(−2)=9×4−4=36−4=32.Now divide the numerator by the denominator to get the value of dxdy at the point (−4,−2): (dxdy)∣(−4,−2)=−329.
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