You cannot. The cosine of 30 degrees is an irrational number.
Cosine(30) = sqrt(3)/2
cos(30) = sqrt(3)/2 so cosine squared is 3/4.
0.866 ( or (sqrt 3)/2 )
cos(30 deg) = sqrt(3)/2 = 0.8660 approx.
It is cosine*cosine*cosine.
As a decimal: 0.866 As a fraction: √(3)/2
The length of the other two sides is 7 cosine (60) and 7 cosine (30)that is 3.5 and 6.062 cmthe perimeter = 7 + 3.5 + 6.062 = 16.562 cm
what is the cosine of 3.14 ?
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.
mostly it comes from memorization. If sin 30 = 1/2, then arcsin (1/2) = 30