The power family \(y=ax^n\), with nonzero constant \(a\), includes exponents \(0,1,2,3\). For \(n=0\), use the constant function \(y=a\), including at \(x=0\); no evaluation of \(0^0\) is needed.
| Power | Shape for positive coefficient |
|---|---|
| \(n=0\) | Horizontal line |
| \(n=1\) | Straight line through the origin |
| \(n=2\) | Upward-opening parabola, symmetric about the y-axis |
| \(n=3\) | Increasing cubic curve through the origin |
Example
The sketches show \(y=x^2\) and \(y=x^3\). At \(x=-2\), their values are \(4\) and \(-8\), respectively. The square graph has equal outputs at opposite inputs; the cube graph has opposite outputs.
Multiplying by a negative coefficient reverses every output sign, reflecting the graph in the horizontal axis. The graph of \(y=-x^2\) therefore opens downward; \(y=-x^3\) decreases from left to right.
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