Thread: injective function

Dear all,

please help me solving this question

Determine whether the function is injective or surjective.

f (X) = X3 – X

Do you know what the terms mean?

Injective = For any a and b in the domain, f(a) = f(b) implies a = b. (They map to distinct elements)

Surjective = For any y in the range, there exists an x such that f(x) = y. (Every element in the range has a corresponding element in the domain)

Assuming you mean then you can factor it and see if the two properties hold.

Hint: Look at the roots of the polynomial. Also, is this in the reals or the complex?

Originally Posted by zeeshan4u3

Dear all,

please help me solving this question

Determine whether the function is injective or surjective.

f (X) = X3 – X

Asked (by a different member it would seem) and answered here: http://www.mathhelpforum.com/math-he...nly-maths.html