Q. If y−x3+2y2=5 then find dxdy at the point (1,−2).Answer: dxdy∣∣(1,−2)=
Differentiate Equation: Differentiate both sides of the equation with respect to x. We have y−x3+2y2=5. To find dxdy, we need to differentiate each term with respect to x. Remember that y is a function of x, so we will use the chain rule for the terms involving y. Differentiating y with respect to x gives dxdy. Differentiating y−x3+2y2=50 with respect to x gives y−x3+2y2=52. Differentiating y−x3+2y2=53 with respect to x gives y−x3+2y2=55 using the chain rule. The constant y−x3+2y2=56 differentiates to y−x3+2y2=57. So, the differentiated equation is: y−x3+2y2=58
Solve for dxdy: Solve for dxdy. We have dxdy−3x2+4ydxdy=0. Rearrange the terms to isolate dxdy: dxdy+4ydxdy=3x2 Factor out dxdy: dxdy(1+4y)=3x2 Divide both sides by (1+4y) to solve for dxdy: dxdy=(1+4y)3x2
Substitute Point: Substitute the point (1,−2) into the derivative to find the slope at that point.We have dxdy=1+4y3x2.Substitute x=1 and y=−2:dxdy∣∣(1,−2)=1+4(−2)3(1)2Calculate the denominator:1+4(−2)=1−8=−7Calculate the numerator:3(1)2=3Now, divide the numerator by the denominator:dxdy∣∣(1,−2)=−73
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