In trigonometry, the cotangent is the reciprocal of the tangent. The formula for determining the tangent is the opposite side divided by the adjacent side of a triangle. So, since the cotangent is the reciprocal, then the formula for determining the cotangent is the adjacent side divided by the opposite side of the triangle. When inputting cotangent into a graphing calculator, you need to know the angle in degrees for which you are trying to find the cotangent.
Things You'll Need
 Graphing calculator

Type "1" into your graphing calculator.

Press the division sign. The calculator is now prepared to perform a reciprocal calculation.

Press the button marked "TAN."

Type the angle for which you are calculating the cotangent.

Press "ENTER" to solve for the cotangent.
References
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