Q. Let x2+y2=25.What is the value of dx2d2y at the point (4,3) ?Give an exact number.
Implicit Differentiation: We are given the equation of a circlex2+y2=25. To find the value of dx2d2y at the point (4,3), we first need to implicitly differentiate the equation with respect to x to find dxdy.Differentiating both sides of the equation with respect to x, we get:2x+2ydxdy=0
Finding dxdy: Now we solve for dxdy: 2y(dxdy)=−2x dxdy=2y−2x dxdy=y−x
Substitute Point: We substitute the point (4,3) into the equation for dxdy to find its value at that point:(dxdy) at (4,3)=−34
Second Derivative: Next, we need to differentiate dxdy with respect to x again to find dx2d2y. This is the second derivative we are looking for.Differentiating −yx with respect to x, we get:dx2d2y=dxd(−yx)
Quotient Rule: To differentiate −x/y, we will use the quotient rule: (vdu−udv)/v2, where u=−x and v=y. Let's find dxdu and dxdv: dxdu=dxd(−x)=−1dxdv=dxd(y)=dxdy (which we found earlier to be −x/y)
Simplify Expression: Now we apply the quotient rule:dx2d2y=y2y(−1)−(−x)(−yx)dx2d2y=y2−y−yx2
Substitute Point: We simplify the expression: dx2d2y=y3−y2−x2
Substitute Point: We simplify the expression:d2y/dx2=(−y2−x2)/y3Now we substitute the point (4,3) into the equation for d2y/dx2 to find its value at that point:d2y/dx2 at (4,3) = (−(3)2−(4)2)/(3)3d2y/dx2 at (4,3) = (−9−16)/27d2y/dx2 at (4,3) = (4,3)1