English name: cosine
Cosine (cosine function), a kind of trigonometric function. In Rt△ABC (right triangle), ∠C = 90, AB is the opposite side C of ∠ C, BC is the opposite side A of ∠A, AC is the opposite side B of ∠B, and the cosine function is cosA=b/c, that is, cosA=AC/AB (in this right triangle, the angle
In the acute trigonometric function, if there is a right triangle, the included angle θ between the right side A, B, hypotenuse C, A and C, then the symbol COS θ = A/C is defined.
In a general trigonometric function, if there is a coordinate plane with a little M(x, y) on it, and the angle θ between OM and the positive semi-axis of X, we define cosθ=x/OM, and for the unit, let OM=r, we say COS θ = X/R. ..
Similar triangles theorem can be used to explain that cosθ is only related to θ, so x/r is constant.
Cosine (cosine function), a kind of trigonometric function. In Rt△ABC (right triangle), ∠ c = 90 (as shown in the figure), and the cosine of ∠A is the hypotenuse of the adjacent side of the triangle, that is, cosA=b/c, which can also be written as cosa=AC/AB.
Cosine function: f(x)=cosx(x∈R)
reference data
Baidu knows:/question/623931610340931964.html.