A function value in a height model pairs a time with a height. The number inside the parentheses tells you when, and the value after the equals sign tells you how high the object is then. You can define the function and evaluate it in Desmos to check the value. Don’t swap the units or mistake one height for the maximum.
Hints
- Hint 1
In , the number inside the parentheses is the input: it replaces . The problem measures in seconds after launch. What time does refer to?
- Hint 2
The value of is an output, so it uses the function’s unit: meters of height. A maximum would be the highest height of the whole flight. Does one function value make that claim?
Step-by-step
Read the input and output
Step 1Identify what the input measures
The number inside is the input: it replaces . Since counts seconds after launch, the input tells when; the output tells how high. So means seconds after launch, not meters.
- Step 2
Check the function value
Type in Desmos, then type . Desmos displays , confirming that the output at this time is .
- Step 3
Put the value into words
The output uses the height unit, meters. So the firework is meters above the ground seconds after launch. That describes its height at one time, not its maximum height. Choice D.