AP EAMCET201822 Apr 2018Morning ShiftMathematicsApplication of DerivativesActual
If x and y are two positive numbers such that x+y=32 , then the minimum value of x^2+y^2 is,
Options
- A500
- B256
- C1024
- D512
Correct answer
D. 512
Step-by-step solution
aligned & Let, s=x^2+y^2 & =x^2+(32-x)^2 [ x+y=32] & d s d x =2 x+2(32-x)(-1) & =2 x-2(32-x) & =2 x-64+2 x & =4 x-64 & aligned For maxima or minima, array rlrl d s d x & =0 4 x-64 & =0 x & =16 & and y & =32-x=32-16=16 array Again, d^2 s d x =4=+ ive s is minimum when x=y=16 Minimum value of s=16^2+16^2=256+256=512