1. **Understanding Exponential Functions:**
An exponential function has the form $$y = a \cdot b^x$$ where $a \neq 0$, $b > 0$, and $b \neq 1$. The base $b$ determines the growth or decay.
2. **Finding the y-intercept:**
The y-intercept occurs when $x=0$. Substitute $x=0$ into the function:
$$y = a \cdot b^0 = a \cdot 1 = a$$
So, the y-intercept is at $(0, a)$.
3. **Finding the x-intercept:**
The x-intercept occurs when $y=0$. Set the function equal to zero:
$$0 = a \cdot b^x$$
Since $a \neq 0$ and $b^x > 0$ for all real $x$, the function never equals zero.
Therefore, there is **no x-intercept**.
4. **Finding the asymptote:**
Exponential functions have a horizontal asymptote. For $$y = a \cdot b^x + c$$ the asymptote is $y = c$.
If $c=0$, the asymptote is the x-axis: $$y=0$$.
5. **Plotting the function:**
- Plot the y-intercept at $(0, a)$.
- Choose several $x$ values (e.g., $-2, -1, 1, 2$) and calculate corresponding $y$ values.
- Draw a smooth curve through these points approaching the asymptote.
Example: For $$y = 2 \cdot 3^x$$
- y-intercept: $(0, 2)$
- Asymptote: $y=0$
- Points: $x=-1 \Rightarrow y=2 \cdot 3^{-1} = \frac{2}{3}$, $x=1 \Rightarrow y=6$
This shows exponential growth.
**Summary:**
- y-intercept at $(0, a)$
- No x-intercept
- Horizontal asymptote at $y=c$
- Plot points and draw curve approaching asymptote
Exponential Functions
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