cos(39)

<-- Enter angle or number for inverse functions. Enter PI for π


Calculate cos(39)°
Since our angle is between 0 and 90 degrees, it is located in Quadrant I
In the first quadrant, the values for sin, cos and tan are positive.

39 is an acute angle since it is less than 90°
cos(39) = 0.45

In Microsoft Excel or , you write this function as =COS(RADIANS(39))

Since 39° is less than 90, we can express this in terms of a cofunction
cos(θ) = sin(90 - θ) = sin(90 - 39) = sin(51)

Important Angle Summary
θ°θradianssin(θ)cos(θ)tan(θ)csc(θ)sec(θ)cot(θ)
0010010
30°π/61/23/23/322√3/33
45°π/42/22/21221
60°π/33/21/232√3/323/3
90°π/210N/A10N/A
120°2π/33/2-1/2-√32√3/3-2-√3/3
135°3π/42/2-√2/2-12-√2-1
150°5π/61/2-√3/2-√3/32-2√3/3-√3
180°π0-100-1N/A
210°7π/6-1/2-√3/23/3-2-2√3/3-√3
225°5π/4-√2/2-√2/21-√2-√21
240°4π/3-√3/2-1/2-√3-2√3/3-2-√3/3
270°3π/2-10N/A-10N/A
300°5π/3-√3/21/2-√3-2√3/32-√3/3
315°7π/4-√2/22/2-1-√22-1
330°11π/6-1/23/2-√3/3-22√3/3-√3