Texas Instruments TI-80 Manual Book page 175

5. Enter the expressions to define the line Y=X, about which
the graph of the function and the graph of its inverse are
symmetric. That is, the reflection of the graph of the
function through the line Y=X produces the graph of its
inverse.
X3î=T
Y3î=T
6. Press , to plot the graph. Press +, and then
press 9 several times (until the cursor appears). Next,
press 8 and 7 several times to move the cursor from a
point on the relation to the reflected point and back again.
Note: The expressions to define the inverse can be
generalized.
X1î=Y2î
Y1î=X2î
Applications 11-11