# HOW TO: Find the Secant, Cosecant, or Cotangent of an Angle in Excel 2000

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## SUMMARY

Microsoft Excel 2000 has built-in functions for a large number of trigonometric functions but does not include all such functions. However, you can derive functions from existing functions by using an Excel formula.

Some functions that you can derive from built-in Excel functions include the following:
• Secant (SEC)
• Cosecant (CSC)
• Cotangent (COT)
These functions are the inverse of the cosine, sine, and tangent, respectively.

### Formulas for Derived Trigonometric Functions

To calculate these additional functions, use the following formulas, where angle is the measure of the angle in radians:
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: Trigonometric functions in Excel must use angles measured in radians rather than in degrees. To convert an angle from degrees to radians, multiply the angle in degrees by PI()/180.

## REFERENCES

For more information about trigonometric functions, click Microsoft Excel Help on the Help menu, type trigonometric functions in the Office Assistant or the Answer Wizard, and then click Search to view the topics returned.

## Properties

Article ID: 213887 - Last Review: September 27, 2003 - Revision: 3.1
##### APPLIES TO
• Microsoft Excel 2000 Standard Edition
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