Q. If −y+y3−3y2+3x2=0 then find dxdy at the point (−1,3).Answer: dxdy∣∣(−1,3)=
Implicit Differentiation: To find the derivative dxdy, we need to implicitly differentiate the given equation with respect to x. The equation is −y+y3−3y2+3x2=0.
Chain Rule Application: Differentiate each term with respect to x. For terms with y, we use the chain rule, treating y as a function of x (y(x)). The derivative of −y with respect to x is −dxdy. The derivative of y3 with respect to x is y0 by the chain rule. The derivative of y1 with respect to x is y3 by the chain rule. The derivative of y4 with respect to x is y6.
Grouping Terms: Writing the derivatives out, we get: −dxdy+3y2dxdy−6ydxdy+6x=0.
Factor Out dxdy: Now we group the terms with dxdy on one side and the term with x on the other side:−dxdy+3y2⋅dxdy−6y⋅dxdy=−6x.
Solve for dxdy: Factor out dxdy from the left side of the equation:dxdy×(−1+3y2−6y)=−6x.
Substitute Values: Solve for dxdy by dividing both sides by (−1+3y2−6y):dxdy=(−1+3y2−6y)−6x.
Calculate Denominator: Now we need to evaluate dxdy at the point (−1,3). Substitute x=−1 and y=3 into the equation:dxdy∣∣(−1,3)=(−1+3(3)2−6(3))−6(−1).
Calculate Numerator: Calculate the denominator:−1+3(3)2−6(3)=−1+3(9)−18=−1+27−18=8.
Divide to Find dxdy: Calculate the numerator:−6(−1)=6.
Simplify Fraction: Now, divide the numerator by the denominator to find dy/dx at the point (−1,3):dy/dx∣(−1,3)=86.
Simplify Fraction: Now, divide the numerator by the denominator to find dxdy at the point (−1,3): dxdy∣∣(−1,3)=86. Simplify the fraction: dxdy∣∣(−1,3)=43.
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