2021 Fall AMC 10A Problems/Problem 16
Problem
The graph of is symmetric about which of the following? (Here
is the greatest integer not exceeding
.)
Solution 1 (Graphing)
Let and
Note that the graph of
is a reflection of the graph of
about the
-axis, followed by a translation of
unit right.
The graph of is shown below:
The graph of
is shown below:
The graph of
is shown below:
Therefore, the graph of is symmetric about
~MRENTHUSIASM
Solution 2 (Piecewise Function)
For all and
note that:
and
We rewrite as
We apply casework to the value of
and
and
and
It follows that
It follows that
It follows that
It follows that
It follows that
It follows that
Together, we have
so the graph of
is symmetric about
Remark
Certainly, if we read the answer choices sooner, then we can stop after Case 3 and eliminate and
This leaves us with
~MRENTHUSIASM
See Also
2021 Fall AMC 10A (Problems • Answer Key • Resources) | ||
Preceded by Problem 15 |
Followed by Problem 17 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
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