Manipal MET2014MathematicsFunctions
If f(x+y)=f(x) f(y) for all x and y and f(15)=2, f^ (0)=3 , then f^ (5) will be
Options
- A2
- B4
- C6
- D8
Correct answer
C. 6
Step-by-step solution
Let x=5, y=0 f(5+0)=f(5) f(0) aligned f(5) & =f(5) f(0) f(0)=1 f^ (5) _ h 0 & = f(5+h)-f(5) h & = _ h 0 f(5) f(h)-f(5) h & = _ h 0 2 ( f(h)-1 h ) [ f(5)=2] & =2 _ h 0 ( f(h)-f(0) h )=2 f(0) & =2 3=6 aligned