Chapter 7: Problem 82
If \(f(x)=\sqrt{2 x+3}\) and \(g(x)=\sqrt[3]{x-8},\) find the following function values. $$ f(3) $$
Short Answer
Expert verified
The value of \( f(3) \) is 3.
Step by step solution
01
Understand the Given Function
We are given the function \( f(x) = \sqrt{2x + 3} \). We need to evaluate this function at \( x = 3 \) to find \( f(3) \).
02
Substitute into the Function
Substitute \( x = 3 \) into the function \( f(x) = \sqrt{2x + 3} \). This yields: \( f(3) = \sqrt{2(3) + 3} \).
03
Calculate Inside the Square Root
Calculate the expression inside the square root: \( 2(3) + 3 = 6 + 3 = 9 \).
04
Solve the Square Root
Find the square root of the result from Step 3: \( \sqrt{9} = 3 \).
05
Conclusion: Final Function Value
The value of the function \( f(3) \) is \( 3 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Function Evaluation
Evaluating a function means finding the output value of that function for a specific input value. If you have a function, say \( f(x) \), evaluating \( f(3) \) involves replacing \( x \) in the function with 3 and then simplifying to get an answer. Function evaluation is a critical skill in algebra because it shows how functions transform or map inputs to outputs.
- Think of a function as a mathematical machine that takes an input, does something to it, and then gives you an output.
- In our example, we need to evaluate \( f(3) \) which requires substituting 3 into the function \( f(x)=\sqrt{2x+3} \).
- This involves straightforward substitution followed by basic mathematical operations like addition and finding square roots.
Square Roots
The square root is a special mathematical function that, when applied to a number, gives the value which, when multiplied by itself, results in the original number. For instance, the square root of 9 is 3 because 3 multiplied by itself is 9.
- In mathematical terms, the square root of a number \( y \) is a number \( x \) such that \( x^2=y \).
- Using the radical symbol \( \sqrt{} \), we express it as \( \sqrt{y} = x \).
- For positive integer outcomes, square roots are relatively simple, but finding square roots of non-perfect squares requires a more complex approach.
Substitution in Functions
Substitution is a vital technique used to evaluate functions and solve algebraic expressions by replacing a variable with a specific value or another expression.
- When substituting into a function, you literally "switch out" the variable – in our case \( x \) – with a given number or term.
- This allows us to find specific outputs of the function, also known as function values, for particular inputs.
- In the given exercise, substituting \( x = 3 \) involved replacing \( x \) in \( f(x)=\sqrt{2x+3} \) to compute \( f(3) \).