If `f(x+y)=f(x).f(y) and f(1)=4`.Find `sum_(r=1)^n f(r)`

If f:R rarr R satisfies,f(x+y)=f(x)+f(y),AA x,y in R and f(1)=4,thensum_(r=1)^(n)f(r)

If f(x+y)=f(x)f(y) for all x,y in R,f(1)=2 and a_(r)=f(r) for r in N then the co-ordinates of a point on the parabola y^(2)=8x whose focal distance is 4 may be.

If f:RtoR satisfies f(x+y)=f(x)+f(y) for all x,y in R and f(1)=7, then sum_(r=1)^(n) f(r) , is

If f:RtoR satisfies f(x+y)=f(x)+f(y), for all real x,y and f(1)=m. then: sum_(r=1)^(n)f(r)=

If f (x) is a function such that f(x+y)=f(x)+f(y) and f(1)=7" then "underset(r=1)overset(n)sum f(r) is equal to :

If f(x+y)=f(x)f(y) and sum_(x=1)^(oo)f(x)=2,x,y in N , where N is the set of all natural numbers , then the value of (f(4))/(f(2)) is :

If f(x)-f(y)=In(x/y)+x-y then find sum_(k=1)^20f'(1/k^2)

If f:R to R satisfies f(x+y)=f(x)+f(y), for all x, y in R and f(1)=7, then sum_(r=1)^(n)f( r) is