Cos(30) = sqrt(3)/2
cos(30) = sqrt(3)/2 so cosine squared is 3/4.
Cos(angle) = adjacent / hypotenuse. Cos(a) = a/h Substitute Cos(X) = 5/13 = 0.384615... A = Cos^*-1( 0.384615 .... A = 67.38013505... degrees.
0.866
0.422618262
It is: cos^-1(12/13) = 22.61986495 degrees
cos(30 deg) = sqrt(3)/2 = 0.8660 approx.
Cos(30) = sqrt(3)/2 = 0.866025403.... ( Which is irrational).
30 degrees explanation 2Cosx-radical 3=0 Then 2cosx=radical 3 and cos x=(radical 3)/2 Now remember that cos 300 is (radical 3)/2 from the 30/60/90 triangle. So the answer is 30 degrees.
510 ~ (510-360) ~ 150 Cos 510 = Cos 150 = - Cos 30 = - ( radical 3 ) / 2
cos(30 = 0.8660254038
cos(30) = sqrt(3)/2 so cosine squared is 3/4.
The value of cos 40 degrees is approximately 0.766.
Cos 43
It is: cos(0) = 1
cos(125) = cos(180 - 55) = cos(180)*cos(55) + sin(180)*sin(55) = -cos(55) since cos(180) = -1, and sin(180) = 0 So A = 55 degrees.
cos 315 degrees is 4th quadrant same as cos (-45) degrees which is +0.7071
cos(30)cos(55)+sin(30)sin(55)=cos(30-55) = cos(-25)=cos(25) Note: cos(a)=cos(-a) for any angle 'a'. cos(a)cos(b)+sin(a)sin(b)=cos(a-b) for any 'a' and 'b'.