The expression is .
In general most of the calculators do not have keys for evaluating the inverse cotangent.
\So we can find the inverse of cotangent value by taking the value of inverse cosine because whose range is the same as inverse cotangent except where undefined.
\Let , then
.
The length of the opposite side is .
The length of the adjacent side is .
The length of the hypotenuse is .
Trigonometric ratio : .
Using calculator find the value of .
Substitute in
.
.
Thus, the value of is
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The value of is
.