Question

\(y=\left\\{\begin{array}{ll}{4-2 x,} & {x \leq 1} \\ {x+1,} & {x>1}\end{array}\right.\)

Short answer

The solution requires the given values of x. Substitute those in either \(y = 4 - 2x\) or \(y = x + 1\), depending on whether x is ≤ 1 or > 1 respectively. No specific solution can be provided without known values of x.

Step-by-step solution

Determine which function to use based on the value of x

When given a value of x, first decide on which function to use. If x ≤ 1, use the first equation: \(y = 4 - 2x\). If x > 1, use the second equation: \(y = x + 1\).

Solve for y

Calculate the equation obtained in the previous step to get the value of y. This would be the answer.

Key concepts

Piecewise Function Definition

A piecewise function is a special type of function that is defined by different expressions, or 'pieces,' depending on the interval of the input value, or 'x'. These functions can appear daunting at first, but they are just a combination of simpler functions, stitched together to cover various ranges of a variable.

Imagine a piecewise function as a choose-your-own-adventure book; depending on the 'x' you're dealing with, you'll flip to a different page (or equation) to find out what 'y' is. Like in our exercise, the function takes on one form, namely \(y = 4 - 2x\), when \(x\) is less than or equal to 1, and it transforms into another form, \(y = x + 1\), when \(x\) is greater than 1. It's a way for mathematicians to describe situations that have different rules or behaviors depending on certain conditions.

Solving Piecewise Functions

Solving a piecewise function requires careful attention to the domain of 'x'. The domain will tell you which 'piece' of the function to use.

Let's say we are given a particular value of \(x\), and we want to find \(y\). The first step is to determine which equation applies to the value of \(x\) you have. If \(x\) is less than or equal to 1, as in our textbook exercise, we'll use the first equation, \(y = 4 - 2x\). But if \(x\) is greater than 1, we'll switch to the second equation, \(y = x + 1\). After picking the right equation, simply plug in the value of \(x\) and solve for \(y\). This approach allows us to work with complex real-world situations where different rules apply in different scenarios.

Graphing Piecewise Functions

Graphing piecewise functions can be thought of as drawing separate lines or curves for each 'piece' of the function on the same coordinate plane. You'll often end up with a graph that looks like it's made up of different sections -- because it is!

When graphing the function from our exercise, you would draw a line for \(y = 4 - 2x\) that only continues until \(x = 1\). At that point, you'd 'jump' to the second part of the function, \(y = x + 1\), and continue the graph with this new line. Do remember to indicate whether the endpoint of each 'piece' is included or not by using a solid dot for an included endpoint or an open circle for an endpoint that's not part of that piece. By combining these visual segments, you can effectively communicate the behavior of the piecewise function across its entire domain.