Skip to main contentSkip to solution

An energy DRONE is flying along the curve y=x2+7y = x^2 + 7. A soldier is placed at (3,7)(3, 7). The nearest distance of the DRONE from soldier's position is

Solution

✅ Correct Option: 3

Let the point on the curve be (a,a2+7)(a, a^2+7). Square of distance from (3,7)(3,7): D2=(a−3)2+a4D^2 = (a-3)^2 + a^4. Minimising: d(D2)da=2(a−3)+4a3=0\frac{d(D^2)}{da} = 2(a-3) + 4a^3 = 0, giving 2a3+a−3=02a^3 + a - 3 = 0, so a=1a = 1. Then point is (1,8)(1, 8) and distance =(1−3)2+(8−7)2=4+1=5= \sqrt{(1-3)^2 + (8-7)^2} = \sqrt{4+1} = \sqrt{5}.

Keyboard Shortcuts

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