Cosine Graph
Main Concept
The cosine function is one of the three primary trigonometric functions. In a right triangle, the cosine is the ratio between the length of the side adjacent to the angle and the length of the hypotenuse.
cosθ = AdjacentHypotenuse
Special values of cosine
θ
0
π2
π
3 π2
2 π
cosθ
1
−1
Notice the pattern
π6
π4
π3
π2
42
32
22
12
02
Explore by rotating the hypotenuse about the circle's center. By calculating the ratio adjacent/hypotenuse for different values of θ, we can construct the graph of cosθ. Change the value of r with the slider and notice that this ratio is not affected.
r =
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MathApps/Trigonometry
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