Because it is not always convenient to convert to convert sin to cos when working with adjacent sides.
Reciprocal of Cosine is Secant
Cosine of -90 is 0.
it would be secant, 1/cosine
[ cos(Θ) ]-1 = 1/cosine(Θ) = secant(Θ)
0.525321989
cosine = adjacent/hypotenuse. It can be used as other trig functions can.
because sine & cosine functions are periodic.
It is cosine*cosine*cosine.
Sides have lenght, angles do not. Cosine is the ratio of the adjacent side to the hypotenuse. Cosine can be used to find either of these sides if the other is known.
in trigonometry
sine and cosine
Inverse of Cosine is 'ArcCos' or Cos^(-1) The reciprocal of Cosine is !/ Cosine = Secant.
Cosine of 1 degree is about 0.999848. Cosine of 1 radian is about 0.540302.
Tangent = sine/cosine provided that cosine is non-zero. When cosine is 0, then tangent is undefined.
The inverse of the cosine is the secant.
Reciprocal of Cosine is Secant
Cosine is 0.995