# What does it mean if a linear transformation is one-to-one?

## What does it mean if a linear transformation is one-to-one?

A linear transformation T:Rn↦Rm is called one to one (often written as 1−1) if whenever →x1≠→x2 it follows that : T(→x1)≠T(→x2) Equivalently, if T(→x1)=T(→x2), then →x1=→x2. Thus, T is one to one if it never takes two different vectors to the same vector.

## How do you know if a linear transformation is one-to-one?

If there is a pivot in each column of the matrix, then the columns of the matrix are linearly indepen- dent, hence the linear transformation is one-to-one; if there is a pivot in each row of the matrix, then the columns of A span the codomain Rm, hence the linear transformation is onto.

What does it mean to be onto linear algebra?

A function y = f(x) is said to be onto (its codomain) if, for every y (in the codomain), there is an x such that y = f(x).

What does it mean if a function is one-to-one?

A function f is 1 -to- 1 if no two elements in the domain of f correspond to the same element in the range of f . In other words, each x in the domain has exactly one image in the range. If no horizontal line intersects the graph of the function f in more than one point, then the function is 1 -to- 1 .

### What is the difference between one-to-one and onto?

Definition. A function f : A → B is one-to-one if for each b ∈ B there is at most one a ∈ A with f(a) = b. It is onto if for each b ∈ B there is at least one a ∈ A with f(a) = b. It is a one-to-one correspondence or bijection if it is both one-to-one and onto.

### What is the difference between onto and one-to-one?

The horizontal line y = b crosses the graph of y = f(x) at precisely the points where f(x) = b. So f is one-to-one if no horizontal line crosses the graph more than once, and onto if every horizontal line crosses the graph at least once.

What is the difference between onto and one to one?

How do you prove onto?

To prove a function, f : A → B is surjective, or onto, we must show f(A) = B. In other words, we must show the two sets, f(A) and B, are equal. We already know that f(A) ⊆ B if f is a well-defined function.

#### How do I determine if a function is one-to-one?

An easy way to determine whether a function is a one-to-one function is to use the horizontal line test on the graph of the function. To do this, draw horizontal lines through the graph. If any horizontal line intersects the graph more than once, then the graph does not represent a one-to-one function.