A function takes an input and produces an output using a rule. When the input is given, define the function in Desmos and enter that input to get the output. In a term like , square the input before multiplying by the coefficient. Squaring the whole product instead is a different calculation.
Hints
- Hint 1
In function notation, the number in parentheses is the input. If is , what would you type after defining to ask Desmos for its output?
- Hint 2
The exponent in applies to , not to . So Desmos will square the input first, then multiply by and subtract .
Step-by-step
Define and evaluate in Desmos
Step 1Enter the function rule
Type in Desmos. A function is a rule that turns an input into an output. Defining lets you enter the given input on the next line without retyping the rule.
- Step 2
Find the output at the given input
Since , type . Desmos shows : it squares , multiplies by , then subtracts . The square applies to alone, not to . So the value of when is . Choice D.