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 tangent function is tanB=b/a, that is, tanB=AC/BC. ?
Six basic functions:
Function name: sine function, cosine function, tangent function, cotangent function, secant function, cotangent function.
Sine function: sinθ=y/r
Cosine function: cosθ=x/r
Tangent function: tanθ=y/x
Cotangent function: cotθ=x/y
Secθ=r/x secθ = r/x
Cotangent function: csθ= r/y