Geometric Proof of the Cosine of Sum Formula
2020-04-10 00:30
This GeoGebra applet visually demonstrates the geometric proof of the cosine of sum formula (cos(α+β) = cosαcosβ - sinαsinβ). By constructing circles, segments, orthogonal lines, and angles, it illustrates the geometric meaning of this trigonometric identity using congruent triangles and transformations, making it an excellent tool for high school or college trigonometry education.
In collections
Secondary Vocational Mathematics
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