Use a calculator in radian mode to find an approximate value

Use a calculator (in radian mode) to find an approximate value of the expression correct to five decimal places, if it is defined. (If an answer is undefined, enter UNDEFINED.) tan1(1.23458)

Solution

tan^-1 (1.23458) =0.88999 radians from calculator.

In degrees, arctan (1.23458) =50.99280 degrees