The function youβve given is
f(x)=β3x+12β3xββ
where the notation
βyβ
represents the greatest integer less than or equal to
y
.
Letβs evaluate this function for a few values:
For
x=1
,
f(1)=β3(1)+12β3(1)ββ=β4β1ββ=β1
because the greatest integer less than
β1/4
is
β1
.For
x=2
,
f(2)=β3(2)+12β3(2)ββ=β7β4ββ=β1
because the greatest integer less than
β4/7
is
β1
.
You can see a pattern here. The function
f(x)
is always equal to
β1
for all positive integers
x
. This is because the numerator
2β3x
is always negative and the denominator
3x+1
is always positive for all positive integers
x
. The fraction is thus a negative number between
0
and
β1
, and the floor of this number is always
β1
.
Therefore, the sum
f(1)+f(2)+f(3)+β―+f(999)+f(1000)
is simply
β1
added to itself
1000
times, which equals
β1000
. So, the value of the given expression is
β1000
.