Indonesian University Entrance 2015
Hi guys, so this is my question from my last exam on SBMPTN 2015. It's an Indonesian exam to qualify students that wants to entrance Public Universities. This is the basic skill question:
a function states that:
f(-x) = -f(x) for every real numbers
and if we have
f (3) = -5
f(-5) = 1
what is f(f(-3))?
The answer is -1.
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1 solution
f(f(-3)) = f(-(f(3))
since f(3) = -5
we change the function
f(-(f(3)) = f(-(-5)
which made the function
f(-(-5) = f(5)
we know from the question that
f(-x) = - f(x)
so,
f(-5) = - f (5)
where f(5) = 1
so the answer is -1.
or f(f(-3)) = f(-(f(3))
f(-(f(3)) = f(-(-5)
f(-(-5) = f(5)
f(-5) = - f (5)
so the answer is -1.