The reciprocal trigonometric ratios: cotangent
It is said that there are six ratios possible for the lengths of the sides of a
right triangle. You have learned about the sine (sin), cosine (cos), and tangent (tan)
ratios. The three other trigonometric ratios are their reciprocals.
Cotangent (cot): is the reciprocal of tan, i.e. the ratio of the length of the adjacent side to the length of the opposite side.
There is a big difference between cot θ and tan-1x
. The first one means "1/tan θ". The second one involves finding an angle
whose tangent is x
. So on your calculator, don't use your tan-1
button to find cot θ.