Question

How many numbers are reciprocal of themselves?

Answer 1

Answer:

  two: +1 and -1

Step-by-step explanation:

If a number is equal to its own reciprocal, it will satisfy the equation ...

  x = 1/x

Multiplying by x and subtracting 1 gives ...

  x^2 -1 = 0

This factors as ...

  (x -1)(x +1) = 0

By the zero product rule, the solutions are those values of x that make one or more factors zero:

  x = 1

  x = -1

There are two self-reciprocals.