Apple iWork '09 - Manual (Page 338)

TAN
The TAN function returns the tangent of an angle that is expressed in radians.
TAN(radian-angle)
 radian-angle: An angle, expressed in radians. radian-angle is a number value.
Although it can be any value, it would normally be in the range –pi to +pi.
Usage Notes
The tangent is the ratio of the sine to the cosine. Â
To return an angle in degrees, use the DEGREES function (to convert radians to Â
degrees) with this function; that is, =DEGREES(TAN(radian-angle)).
Examples
=TAN(1) returns 1.557407725, the tangent of 1 radian (approximately 57.3 degrees).
=TAN(RADIANS(45)) returns 1, the tangent of a 45-degree angle.
=TAN(3*PI()/4) returns -1.
Related Topics
For related functions and additional information, see:
“ATAN” on page 330
“ATAN2” on page 331
“ATANH” on page 332
“COS” on page 333
“DEGREES” on page 334
“SIN” on page 336
“TANH” on page 339
“Listing of Trigonometric Functions” on page 326
“Value Types” on page 36
“The Elements of Formulas” on page 15
“Using the Keyboard and Mouse to Create and Edit Formulas” on page 26
“Pasting from Examples in Help” on page 41
338 Chapter 12 Trigonometric Functions