# How to Find Secant, Cosecant, or Cotangent of an Angle

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## SUMMARY

Microsoft Excel has built-in functions for a large number of trigonometric functions, but does not include all such functions. However, those not included may be derived from existing functions by using a formula in Microsoft Excel.

Some functions that may be derived from built-in Excel functions include:
secant (SEC)
cosecant (CSC)
cotangent (COT)
These functions are the inverse of the cosine, sine, and tangent, respectively. To calculate these additional functions where "angle" is the measure of the angle in radians, use the following formulas:
SEC(angle) = 1/COS(angle)

CSC(angle) = 1/SIN(angle)

COT(angle) = 1/TAN(angle)
For example, to find the cotangent of a 30 degree angle, use the following formula:
=1/TAN(30*PI()/180)
NOTE: To convert an angle from degrees to radians, multiply the angle in degrees by PI()/180.

NOTE: Trigonometric functions in Excel must use angles measured in radians rather than in degrees.

For additional information on converting degree angles to radians, please see the following article in the Microsoft Knowledge Base:
41064 XL: Trigonometric Functions Returning Incorrect Values

## REFERENCES

For more information about trigonometric functions, click Contents And Index on the Help menu, click the Index tab in Excel 97 Help, type the following text
trigonometric functions
and then double-click the selected text to go to the "About math and trigonometry functions" topic. If you are unable to find the information you need, ask the Office Assistant.

## Properties

Article ID: 188075 - Last Review: August 17, 2005 - Revision: 1.3
##### APPLIES TO
• Microsoft Excel 97 Standard Edition
• Microsoft Excel 95 Standard Edition
• Microsoft Excel 5.0 Standard Edition
##### Keywords:
kbhowto KB188075
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