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Definition of tangent

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Steve S. | Tutoring in Precalculus, Trig, and Differential CalculusTutoring in Precalculus, Trig, and Diffe...
5.0 5.0 (3 lesson ratings) (3)
For any point on the x-y plane, (x,y) = (r cos(θ), r sin(θ)), where the Initial Ray of θ is the positive x-axis and the Terminal Ray of θ starts at the origin and goes through (x,y).
r = √(x^2+y^2) is the distance from the origin to the point.
sin(θ) = y/r
cos(θ) = x/r
tan(θ) = sin(θ)/cos(θ) = y/x
cot(θ) = 1/tan(θ) = x/y
sec(θ) = 1/cos(θ) = r/x
csc(θ) = 1/sin(θ) = r/y
Philip P. | Effective and Affordable Math TutorEffective and Affordable Math Tutor
5.0 5.0 (437 lesson ratings) (437)
Go to the link below for a quick guide to the definitions and identities of the trig functions, including the tangent.