Can someone provide me with a visual proof (unit circle) that tanx=sinx/cosx? :)

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- Jun 28th 2013, 06:50 AMPazeVisual proof of tan
Can someone provide me with a visual proof (unit circle) that tanx=sinx/cosx? :)

- Jun 28th 2013, 07:13 AMemakarovRe: Visual proof of tan
In fact, tan(x) = sin(x)/cos(x) is often taken to be the definition. Do you need a proof that tan(x) is the length of the tangent to the unit circle, as the orange segment in the following picture (taken from the TikZ manual)?

http://i.imgur.com/79aIpql.png

This is because the two triangles are similar, so tan(α)/sin(α) = 1/cos(α). - Jun 28th 2013, 08:36 AMPazeRe: Visual proof of tan
That clears it up. Thanks!