TCS
Company
Numerical Ability
Algebra
Suppose that the function f is defined on natural numbers (integers>0) such that f(1)=1 &f(x+y)=f(x)+f(y)+3xy+3 for all x,y.whart is the value of f(5)+f(7)? A)140 b)215 c)135 d)129
Read Solution (Total 3)
-
- f(1)=1
f(2)=f(1)+f(1)+3*1*1+3=8
f(3)=f(1)+f(2)+3*1*2+3=1+8+6+3=18
f(4)=f(1)+f(3)+3*1*3+3=1+8+6+3=1+18+9+3=31
f(5)=f(1)+f(4)+3*1*4+3=47
f(7)=f(4)+f(3)+3*4*3+3=88
Hence f(5)+f(7)=135 - 9 years agoHelpfull: Yes(9) No(0)
- Ans : 135
f (1)-1
f (2)-8
f(4)-31
f(5)-47
f (7)-88
F (5)+f (7) - 135 - 9 years agoHelpfull: Yes(2) No(2)
- YEs it is Exactly 135.
- 9 years agoHelpfull: Yes(0) No(1)
TCS Other Question