If cotθ = 2, find all the values of all the trigonometric ratios of θ.
We have, cotθ = 2k/k = base/perpendicular (For some value of k)
By Pythagoras theorem, (hypotenuse)2 = (perpendicular)2 + (base)2
∴AB2 = BC2 + AC2
AB2 = (k)2 + (2k)2
AB2 = k2 + 4k2
AB2 = 5k2 = (k√5)2
→ AB = k√5
Hence, the trignometeric ratios for the given θ are:
sinθ = BC/AB = k/(k√5) = 1/√5
cosθ = AC/AB = (2k)/(k√5) = 2/√5
tanθ = BC/AC = sinθ /cosθ = k/(2k) = 1/2
cotθ = 2
cosecθ = AB/BC = 1/sinθ = √5
secθ = AB/AC = 1/cosθ = √5/2