Answer:
two: +1 and -1
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.