KVPY2016MathematicsDefinite Integration
Let f be a continuous function defined on [0,1] such that ₀¹ f²(x) d x= ( ₀¹ f(x) d x )² . Then the range of f
Options
- Ahas exactly two points
- Bis the interval [0,1]
- Chas more than two points
- Dis a singleton
Correct answer
D. is a singleton
Step-by-step solution
By Cauchy Schwarz inequality _ a ^ b f(x) g(x) d x ² _ a ^ b (f(x))² d x _ a ^ b (g(x))² d x Here g(x)=1 and equality holds only when f ( x ) g ( x ) = So, f(x) is constant