Skip to main contentSkip to solution

If x=log⁡tx = \log t and y=1t2y = \frac{1}{t^2}, then d2ydx2\frac{d^2 y}{d x^2} is equal to

Solution

✅ Correct Option: 2

dxdt=1t\frac{dx}{dt} = \frac{1}{t}, dydt=−2t3\frac{dy}{dt} = -\frac{2}{t^3}. So dydx=−2t3⋅t=−2t2\frac{dy}{dx} = -\frac{2}{t^3} \cdot t = -\frac{2}{t^2}. Then d2ydx2=ddt(−2t2)⋅dtdx=4t3⋅t=4t2\frac{d^2y}{dx^2} = \frac{d}{dt}\left(-\frac{2}{t^2}\right) \cdot \frac{dt}{dx} = \frac{4}{t^3} \cdot t = \frac{4}{t^2}.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question