Question

Which function has an inverse that is also a function? a {(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)} b {(–1, 2), (0, 4), (1, 5), (5, 4), (7, 2)} c {(–1, –2), (0, 4), (1, 3), (5, 14), (7, 4)} d {(–1, 4), (0, 4), (1, 2), (5, 3), (7, 1)}

Answer 1

an expression, that is a function, will have no x-repeats on the x,y pairs.

and expression that is a function, and has an inverse that is also a function, will have no x-repeats, and no y-repeats either, so the pairs will be unique for the set, let's do some checking then,


`\bf a \qquad\{(-1, 3), (0, 4), (1, 14), (5, 6), (7, 2)\}\\\\ b \qquad\{(-1, 2), (0, \stackrel{\downarrow }{4}), (1, 5), (5, \stackrel{\downarrow }{4}), (7, 2)\}\impliedby \begin{array}{llll} \textit{notice the } y-rep eats\\ \textit{thus, no dice} \end{array}`


`\bf c \qquad\{(-1, -2), (0, \stackrel{\downarrow }{4}), (1, 3), (5, 14), (7, \stackrel{\downarrow }{4})\}\impliedby \begin{array}{llll} \textit{notice the } y-rep eats\\ \textit{thus, no dice} \end{array}\\\\ d \qquad\{(-1, \stackrel{\downarrow }{4}), (0, \stackrel{\downarrow }{4}), (1, 2), (5, 3), (7, 1)\}\impliedby \begin{array}{llll} \textit{notice the } y-rep eats\\ \textit{thus, no dice} \end{array}`

Answer 2

Which function has an inverse that is also a function? a {(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)} b {(–1, 2), (0, 4), (1, 5), (5, 4), (7, 2)} c {(–1, –2), (0, 4), (1, 3), (5, 14), (7, 4)} d {(–1, 4), (0, 4), (1, 2), (5, 3), (7, 1)}

Explanation:

It is called the inverse or reciprocal function of f to another function f − 1 that fulfills that:

If f (a) = b, then f − 1 (b) = a.

The inverse of a function when it exists is unique, so that neither "X" nor "Y" can be repeated.

If we analyze the possibilities, in the case of b, c, and d, the value 4 of the "Y" is repeated twice; in the case of a, that does not happen, therefore the answer is: a {(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2) }