Q. Let x4+y2=17.What is the value of dx2d2y at the point (−2,1) ?Give an exact number.
Differentiate Equation: Differentiate both sides of the equation x4+y2=17 with respect to x.Using the power rule for differentiation, the derivative of x4 with respect to x is 4x3, and the derivative of y2 with respect to x is 2y(dxdy) since y is a function of x. The derivative of a constant is x0.So, the differentiation gives us x1.
Solve for dxdy: Solve for dxdy. From the previous step, we have 4x3+2ydxdy=0. Rearrange the equation to solve for dxdy: 2ydxdy=−4x3. Now, divide both sides by 2y to isolate dxdy: dxdy=2y−4x3. Simplify the equation: dxdy=y−2x3.
Differentiate dxdy: Differentiate both sides of the equation dxdy=−y2x3 again with respect to x to find dx2d2y. Using the quotient rule for differentiation, which is v2v(u′)−u(v′), where u=−2x3 and v=y, we get: dx2d2y=y2y(−6x2)−(−2x3)(dxdy).
Substitute dxdy: Substitute the value of dxdy from Step 2 into the equation from Step 3.We have dx2d2y=y2y(−6x2)−(−2x3)(−2x3/y).Simplify the equation: dx2d2y=y2−6x2y+(4x6/y).
Substitute Point: Substitute the point (−2,1) into the equation from Step 4.We have d2y/dx2=[−6(−2)2(1)+(4(−2)6/1)]/12.Calculate the values: d2y/dx2=[−6(4)(1)+(4(64)/1)]/1.Simplify the equation: d2y/dx2=[−24+256]/1.
Calculate Final Value: Calculate the final value of d2y/dx2 at the point (−2,1). We have d2y/dx2=−24+256. Simplify the equation: d2y/dx2=232.
More problems from Operations with rational exponents