1. Exponential Functions
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Start by making a table of values for both functions.
Graph:
Table:
Function | y-intercept | Domain | Range |
---|---|---|---|
f(x)=- 2^x | (0, - 1) | All real numbers | y< 0 |
g(x)=- 2^x-3 | (0, - 4) | All real numbers | y< - 3 |
x | - 1 | 0 | 1 | 2 |
---|---|---|---|---|
f(x)=- 2^x | - 2^(- 1)= - 1/2 | - 2^0= - 1 | - 2^1= - 2 | - 2^2= - 4 |
g(x)=- 2^x-3 | - 2^(- 1)-3= - 3 1/2 | - 2^0-3= - 4 | - 2^1-3= - 5 | - 2^2-3= - 7 |
We see that g(x)=- 2^x-3 is a vertical translation of f(x)=- 2^x down by 3 units. Hence, the y-intercept of g is 3 units below the y-intercept of f. Both functions have the same domain — all real numbers. The range of f is y< 0, and the range of g is y < - 3. Let's show them in a table.
Function | y-intercept | Domain | Range |
---|---|---|---|
f(x)=- 2^x | (0, - 1) | All real numbers | y< 0 |
g(x)=- 2^x-3 | (0, - 4) | All real numbers | y< - 3 |