Calculating Tangents - Without the Calculator

[3trQN]

Im curious if there is a good method of calculating the tangent of an angle without use of a calculator, An approximation or a fast method for mentally calculating it would be ideal.

All suggestions welcome.

 

[Hurkyl]

Memorize the value of the tangent at a few points. Use a differential approximation to find the value of the tangent near one of those points, and use interpolation to find the value of the tangent between those points.

 

[3trQN]

I thank you for your input. Any more suggestions?

 

[SGT]

You can use the formulas for the tangent of the half arc and of the sum of arcs and calculate other tangents from the ones you know.