A function evaluation gives you an input and asks for the output. Replace with the given input, then carry out every operation in the rule. For a square-root function, keep the full expression under the root. In Desmos, define the function and enter the requested input; don't stop at the number beneath the root.
Hints
- Hint 1
In function notation, the number inside the parentheses is the input. It replaces in the rule. After you replace , which whole expression is beneath the square-root bar?
- Hint 2
The square root of a number is the nonnegative number that squares to it. You can define the rule in Desmos and enter . Don't stop at the number under the root.
Step-by-step
Define and evaluate in Desmos
Step 1Put the input into the rule
The in is the input, so replace with : . The rule keeps under one square root. Type in Desmos, with the root bar covering both terms.
- Step 2
Read the function's output
Type on the next line. Desmos shows : , and . The square root is the nonnegative number whose square is the number beneath the root, so is not the output. The value of is . Choice B.