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Numerical Ability
Algebra
2. Assume that f(1)=0 and f(m+n) = f(m) +f(n) +4(9mn-1) for all natural numbers (integers<0) m & n. what is the value of f(17)?
a. 5436
b. 4831
c. 5508
d. 4832
Read Solution (Total 4)
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- f(1+16)=f(1)+f(16)+4(9*16-1)....reduce f(16) as f(1+15)..and so on then upto f(1)
then remaining part is 4(9*16-1)+4(9*15-1).......4(9*1-1)
4[9(16+15...+1)-16]
4[9*8*17-16]
4832 - 10 years agoHelpfull: Yes(19) No(0)
- f(1+1)= 0+0+4*(9-1)=32
f(2+2)=32+32+4*35=204
f(4+4)=204+204+4*143=980
f(8+8)=980+980+4*(9*64-1)=4260
f(1+16)=4260+0+4(9*16-1)=4832(ans) - 9 years agoHelpfull: Yes(8) No(0)
- ans:4832
f(9)=1264
f(8)=980
f(17)=f(9)+f(8)+4(9(72)-1)=4832 bt this included manual work cud anyone suggest me the shortcut.. - 10 years agoHelpfull: Yes(3) No(1)
- integers
- 10 years agoHelpfull: Yes(0) No(0)
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