Q. If −y3−y+2+y2=x2 then find dxdy at the point (4,−2).Answer: dxdy∣∣(4,−2)=
Differentiate with respect to x: First, we need to differentiate both sides of the equation with respect to x to find dxdy.Given equation: −y3−y+2+y2=x2Differentiating both sides with respect to x, we get:dxd(−y3−y+2+y2)=dxd(x2)Since y is a function of x, we will use the chain rule for differentiating terms involving y.
Left side differentiation: Differentiating the left side of the equation with respect to x: dxd(−y3)=−3y2⋅dxdy dxd(−y)=−1⋅dxdy dxd(2)=0 (since the derivative of a constant is 0) dxd(y2)=2y⋅dxdy Adding these up, we get: −3y2⋅dxdy−dxdy+0+2y⋅dxdy Simplifying, we have: (−3y2−1+2y)⋅dxdy
Right side differentiation: Differentiating the right side of the equation with respect to x:dxd(x2)=2x
Solve for dxdy: Now we equate the derivatives from both sides:(−3y2−1+2y)⋅dxdy=2xTo find dxdy, we need to solve for it:dxdy=−3y2−1+2y2x
Substitute point (4,−2): We substitute the point (4,−2) into the equation to find the value of dxdy at that point:(dxdy)∣(4,−2)=−3⋅(−2)2−1+2⋅(−2)2⋅4
Perform calculations: Now we perform the calculations:(dxdy)∣(4,−2)=(−3⋅4−1−4)8(dxdy)∣(4,−2)=(−12−1−4)8(dxdy)∣(4,−2)=(−17)8
Final answer: Simplifying the fraction, we get the final answer: (dxdy)∣(4,−2)=17−8