## Thursday, October 27, 2011

### Trigonometry

When we talks about trigonometry, we will most probably think of trigonometric functions, e.g. sine, cosine, tangent etc. Ever think of how were the graphs of these functions obtained?

Let's consider a right triangle with hypotenus of 1 unit. You may drag the point C below and observe the change of the angle. Recall that

$\sin\theta=\frac{y}{r}$
$\cos\theta=\frac{x}{r}$
$\tan\theta=\frac{y}{x}$

Point E is (x, sin x), point F is (x, cos x) and point G is (x, tan x). Observe the position of point E, F or G as you drag point C. You may choose the desire graph at the right bottom corner of the graph.

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If you wish to know more about trigonometric functions, please click on the function you are interested under Trigonometry at the left column.

Betty, Created with GeoGebra