Most Important Selected Qs for JEE AdvancedMathematicsDefinite Integration
If f(x)= ₀^x[f(x)]⁻¹ d x and ₁^1 [ .f(x) |⁻¹ d x= 2 . , then
Options
- Af(2)=2
- Bf(2)=1 / 2
- Cf^ (2)=2
- D₀^1 f(x) d x= 2
Correct answer
C. f^ (2)=2
Step-by-step solution
f(x)= _a^x 1 f(x) d x f(x)= 1 f(x) 1-0 f(x) f(x)=1 f ( x ) f ^ ( x ) dx = 1 dx ( f ( x ))^2 2 =x+c ....(1) Given _a^1[f(x)]⁻¹ d x= 2 f(1)= 2 From (1), (f(1))^2 2 =1+c c=0f(x)= 2 x But f(1)= 2 f(x)= 2 x f(2)=2f^ (x)= 1 2 x f^ (2)= 1 2 ₀^1 f(x) d x= 2^ 3 / 2 3 f⁻¹(x)= x^2 2 f⁻¹(2)=2