Question 482·Easy·Math

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$g(t)=5(0.4)^{t}$

For the function $g$ defined above, what is the value of $g(2)$ ?

An exponential function has its input in an exponent, as in a number raised to the power $t$ . If you’re given an input and asked for a function value, replace the variable with that input. Define the function in Desmos, then type the requested value to read its output. Keep the number in front as a separate multiplier.

Hints

Hint 1
In function notation, the number inside the parentheses is the input. For $g(2)$ , which part of the rule changes when you put in $2$ ?
Hint 2
An exponent of $2$ means multiplying the base by itself twice. The $5$ is outside the power, so what should Desmos evaluate after you define $g$ ?

Step-by-step

Substitute the input and evaluate
Step 1
Replace the input in the rule
In function notation, $g(2)$ means put $2$ in for $t$ . Only $t$ changes, so $g(2)=5(0.4)^2$ .
Step 2
Read the function value in Desmos
The exponent $2$ applies to $0.4$ , not to the $5$ . Type $g(t)=5(0.4)^t$ , then type $g(2)$ on the next line. Desmos shows $0.8$ , so the value of $g(2)$ is $0.8$ . Replace the input, but keep each part of the rule in its original position. Choice B.

Question 482·Easy·Math

Strategy

Hints

Step-by-step

Lessons that teach this

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Strategy

Hints

Step-by-step

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