KCET2023MathematicsApplication of Derivatives
An enemy fighter jet is flying along the curve, given by y=x^2+2 . A soldier is placed at (3,2) wants to shoot down the jet when it is nearest to him. Then, the nearest distance is
Options
- A6 units
- B2 units
- C5 units
- D3 units
Correct answer
C. 5 units
Step-by-step solution
Let P(x, y) be the position of the jet and the solider is placed at A(3,2) . A P= (x-3)^2+(y-2)^2 As, y= (x^2+2 ) x^2=y-2 (A P)^2=(x-3)^2+x^4=z (say) d z d x =2(x-3)+4 x^3 and d^2 z d x^2 =2+12 x^2 For local points of maxima and minima aligned & d z d x =0 2(x-3)+4 x^3=0 & x=1 and d^2 z d x^2 ( at x=1)=14>0 aligned z is minimum, whe x=1, y=1+2=3 Also, minimum distance = (1-3)^2+(3-2)^2 = 5 units