Let θ be an acute angleMathworldPlanetmathPlanetmath and fix a right triangleMathworldPlanetmath having θ as one of its angles. The trigonometric functionsDlmfMathworldPlanetmath sinθ, cosθ, and tanθ can be defined as:


A mnemonic device for remembering the three given above is sohcahtoaMathworldPlanetmath.

The sohcahtoa can be divided up into three portions of three letters each. The first portion, soh, should recall to memory that sinθ is opposite over hypotenuseMathworldPlanetmath; the second portion, cah, should recall to memory that cosθ is adjacentPlanetmathPlanetmathPlanetmath over hypotenuse; and the third portion, toa, should recall to memory that tanθ is opposite over adjacent.

I would like to thank Mrs. Sue Millikin for teaching me trigonometric functions using this mnemonic device.

Title sohcahtoa
Canonical name Sohcahtoa
Date of creation 2013-03-22 15:59:23
Last modified on 2013-03-22 15:59:23
Owner Wkbj79 (1863)
Last modified by Wkbj79 (1863)
Numerical id 13
Author Wkbj79 (1863)
Entry type Definition
Classification msc 97D40
Classification msc 51-01
Related topic Adjacent2
Related topic Opposite2
Related topic Hypotenuse
Related topic TrigonometryMathworldPlanetmath