KCET2024MathematicsLimits
Let the function satisfy the equation f(x+y)=f(x) f(y) for all x, y R , where f(0) 0 . If f(5)=3 and f^ (0)=2 , then f^ (5) is
Options
- A6
- B0
- C3
- D-6
Correct answer
A. 6
Step-by-step solution
f(x+y)=f(x) f(y) Put x=0, y=5 , we get f(0+5)=f(0) f(5) f(5)[f(0)-1]=0 f(0)=1 Consider f^ (5)= _ h 0 f(5+h)-f(5) h = _ h 0 f(5) f(h)-f(5) h = _ h 0 f(5)[f(h)-1] h =f(5) _ h 0 f(h)-f(0) h =f(5) f^ (0)=2 3=6