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Show that the function f:R→R defined as f(x)=x² is neither injective nor surjective.

User Uko
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Final answer:

The function f(x) = x² is neither injective nor surjective.

Step-by-step explanation:

The function f(x) = x² is neither injective nor surjective.

To show that f(x) is not injective (one-to-one), we need to find two distinct values of x that map to the same value of f(x). We can choose x = 2 and x = -2:

f(2) = 2² = 4 and f(-2) = (-2)² = 4,

So, f(2) = f(-2) = 4. This means that f(x) is not injective.

To show that f(x) is not surjective (onto), we need to find a value in the range of f(x) that does not have a pre-image in the domain of f(x). Let's consider the value y = -1:

If f(x) = -1, then x² = -1. However, there is no real number x that satisfies this equation, as the square of any real number is always non-negative.

Therefore, f(x) = x² is neither injective nor surjective.

User Bwaxxlo
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