A function is its own inverse if it is symmetrical about the line y=x. This is the case for functions t, y, w. Function d(x) = 1/x^2 is symmetrical about the line x=0, but is not symmetrical about the line y=x.
The appropriate choices are ...
a. t(p) = p
b. y(j) = -1/j
c. w(y) = -2/y
The appropriate choices are ...
a. t(p) = p
b. y(j) = -1/j
c. w(y) = -2/y