Q. If 4−5x2−2y2=y3−x then find dxdy at the point (1,−2).Answer: dxdy∣∣(1,−2)=
Differentiate with Chain Rule: First, we need to find the derivative of both sides of the equation with respect to x. This will involve using the chain rule for the terms involving y, since y is a function of x. Differentiate both sides of the equation with respect to x: dxd(4−5x2−2y2)=dxd(y3−x) This gives us: 0−10x−4ydxdy=3y2dxdy−1
Rearrange to Solve: Now, we rearrange the terms to solve for dy/dx:−4y(dy/dx)−3y2(dy/dx)=−10x+1Combine like terms:dy/dx(−4y−3y2)=−10x+1
Isolate dxdy: Next, we isolate dxdy by dividing both sides by (−4y−3y2):dxdy=−4y−3y2−10x+1
Substitute Point: Now we substitute the point (1,−2) into the equation to find the value of dxdy at that point:dxdy∣∣(1,−2)=(−4(−2)−3(−2)2)(−10(1)+1)
Perform Calculations: Perform the calculations:dxdy∣∣(1,−2)=(8−3(4))(−10+1)dxdy∣∣(1,−2)=(8−12)(−9)dxdy∣∣(1,−2)=(−4)(−9)
Simplify Fraction: Finally, simplify the fraction: dxdy∣∣(1,−2)=49
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