Q. If x=t2−1 and y=lnt, what is dx2d2y in terms of t ?(a) −2t41b) 2t41c) −x31d) −−2t21e) 2t21
Find Derivative of : First, we need to find the first derivative of y with respect to t, which is (dy)/(dt).Since y=lnt, we use the derivative of the natural logarithm function.(dy)/(dt)=1/t
Find Derivative of x: Next, we need to find the first derivative of x with respect to t, which is (dx)/(dt).Since x=t2−1, we use the power rule for differentiation.(dx)/(dt)=2t
Find Derivative of y with x: Now, we will find the first derivative of y with respect to x, which is dxdy, using the chain rule.dxdy=dtdy⋅dxdtWe already have dtdy=t1 and dtdx=2t, so we need to find dxdt, which is the reciprocal of dtdx.dxdt=dtdx1=2t1
Substitute Values for dxdy: Substitute the values we have into the chain rule to find dxdy.dxdy=t1⋅2t1=2t21
Find Second Derivative of y with x: Now we need to find the second derivative of y with respect to x, which is dx2d2y. To do this, we differentiate dxdy with respect to x. dx2d2y=dxd(2t21)
Differentiate 2t21 with t: To differentiate (2t21) with respect to x, we need to apply the chain rule again, since t is a function of x. dx2d2y=dtd(2t21)⋅dxdt
Substitute dxdt: First, differentiate 2t21 with respect to t. dtd(2t21)=dtd(2t−2)=−2⋅t−3/2=−t31
Substitute (dt)/(dx): First, differentiate 1/(2t2) with respect to t. dtd(1/(2t2))=dtd(t−2/2)=−2⋅t−3/2=−1/t3Now, substitute (dt)/(dx) from the previous steps. dx2d2y=(−1/t3)⋅(1/(2t)) dx2d2y=−1/(2t4)
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