MHT CET202020 Oct 2020Morning ShiftMathematicsApplication of DerivativesActual
The minimum value of f(x)=a² ² x+b² ² x if a²>b² , is
Options
- Aa²-b²
- Bb²
- Ca²+b²
- Da²
Correct answer
D. a²
Step-by-step solution
Given f(x)=a² ² x+b² ² x=a² ( 1+ 2 x 2 )+b² ( 1- 2 x 2 )= ( a²+b² 2 )+ ( a²-b² 2 ) 2 xf(x) will be maximum when 2 x=1 f ( x ) will be minimum when 2 x =-1 Hence minimum value of f(x) is aligned f(x) &= a²+b² 2 + ( a²-b² 2 )(-1) &= a²+b² 2 - a²-b² 2 =b² aligned