I can't seems to understand this following question:
For which of the following functions is f(A+B)= f(A) + f(B) for all postive numbers A and B?
1) f(x)= X^2
2) f(x)= X+1
3) f(x)=Square root X
4) f(x)=2/X
5) f(x)= -3X
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simplythebest
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thumpin_termis
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Another vote for e.
I find just plugging in numbers to something like this the most intuitive.
let a=1, and b=2
then, go through the answer choices and plug it in:
so if
f(x) = -3x (answer choice e)
then,
f(a) = f(1) = -3(1) = -3
f(b) = f(2) = -3(2) = -6
f(a+b) = f(1+2) = f(3) = -3(3) = -9
thus
f(a+b) = f(a) + f(b)
If you try this out on other answer choices, you'll see that it doesn't fit.
I find just plugging in numbers to something like this the most intuitive.
let a=1, and b=2
then, go through the answer choices and plug it in:
so if
f(x) = -3x (answer choice e)
then,
f(a) = f(1) = -3(1) = -3
f(b) = f(2) = -3(2) = -6
f(a+b) = f(1+2) = f(3) = -3(3) = -9
thus
f(a+b) = f(a) + f(b)
If you try this out on other answer choices, you'll see that it doesn't fit.
