Tuesday 17 March 2009

Cos Tan and Ladders

Don’t forget that the convention is to have a ladder of length 1. If this same ladder (see below) is at an angle of 45 degrees then you know that the distance along the ground from the ladder to the wall is the same as the vertical height. The tangent is the opposite / adjacent so the tangent (usually abbreviated to tan) is 1.

If the ladder is lying on the floor (0 degrees) then the length of the hypotenuse is the same as the adjacent. The cosine is the adjacent / hypotenuse. The cosine tells us the distance to the wall because it tells us about the adjacent. The cosine of 0 degrees (usually abbreviated to cos) is 1.

Once you have the idea of what the sine, cosine and tangent actually mean then you can think about your own ladder and you can make your own sine, cosine and tangent graphs.

That sums it up.

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