Q. If 1−4y2+2y=−x3−y3 then find dxdy at the point (3,−2).Answer: dxdy∣∣(3,−2)=
Differentiate with respect to x: First, we need to differentiate both sides of the equation with respect to x to find dxdy. The equation is 1−4y2+2y=−x3−y3. We will apply the chain rule to differentiate terms involving y with respect to x.
Left side differentiation: Differentiate the left side of the equation with respect to x: dxd(1)−dxd(4y2)+dxd(2y). The derivative of a constant is 0, so dxd(1)=0. For the other terms, we need to use the chain rule because they are functions of y, which is a function of x. So, dxd(4y2)=8ydxdy and dxd(2y)=2dxdy.
Right side differentiation: Differentiate the right side of the equation with respect to x: dxd(−x3)−dxd(y3). The derivative of −x3 with respect to x is −3x2. For the term −dxd(y3), we again use the chain rule, giving us −3y2dxdy.
Combine derivatives: Now we combine the derivatives from both sides to form the equation: 0−8ydxdy+2dxdy=−3x2−3y2dxdy. Simplifying, we get −8ydxdy+2dxdy+3y2dxdy=−3x2.
Factor out dxdy: We can factor out dxdy on the left side of the equation: dxdy(−8y+2+3y2)=−3x2. This gives us dxdy=−8y+2+3y2−3x2.
Substitute point: Now we substitute the point (3,−2) into the equation to find the value of dxdy at that point. Plugging in x=3 and y=−2, we get dxdy=(−8(−2)+2+3(−2)2)−3(3)2.
Calculate value: Calculate the value: dxdy=16+2+3(4)−3(9). This simplifies to dxdy=16+2+12−27.
Simplify denominator: Further simplifying the denominator: dxdy=−3027. This reduces to dxdy=−3027, which can be simplified to dxdy=−109.
More problems from Simplify variable expressions using properties