Table of Contents
Welcome to cos 108°, our post aboutthe cosine of 108 degrees.
For the cosine of 108 degrees we use the abbreviation cos for the trigonometric function together with the degree symbol °, and write it as cos 108°.
If you have been looking for what is cos 108°, or if you have been wondering about cos 108 degrees in radians, then you are right here, too.
In this post you can find the cos 108° value, along with identities.
Read on to learn all about the cos of 108°.
Cos 108 Degrees
If you want to know what is cos 108 degrees in terms of trigonometry, then navigate straight to the explanations in the next paragraph; what’s ahead in this section is the value of cos 108°:
cos 108° = -0.30902
cos 108 degrees = -0.30902
The cos of 108 degrees is -0.30902, the same as cos of 108 degrees in radians. To obtain 108 degrees in radian multiply 108° by $\pi$ / 180° = 3/5 $\pi$. Cos 108degrees = cos (3/5 × $\pi)$.
Our results of cos108° have been rounded to five decimal places. If you want cosine 108° with higher accuracy, then use the calculator below; our tool displays ten decimal places.
To calculate cos 108 degrees insert the angle 108 in the field labelled °, but if you want to calculate cos 108 in radians, then you have to press the swap unit button first.
Calculate cos [degrees]
The identities of cosine 108° are as follows:
= sin (90°+108°) = sin 198°
= sin (90°-108°) = sin -18°
-cos108°
= cos (180°+108°) = cos 288°
= cos (180°-108°) = cos 72°
There are more formulas for the double angle (2 × 108°), half angle ((108/2)°) as well as the sum, difference and products of two angles such as 108° and β.
You can locate all of them in the respective article found in the header menu. To find everything about cos -108° click the link. And here is all about sin 108°, including, for instance, a converter.
In terms of the other five trigonometric functions, cos of 108° =
- $\pm \sqrt{1-\sin^{2} 108 ^\circ}$
- $\pm\frac{1}{\sqrt{1 + \tan^{2} 108^\circ}}$
- $\pm\frac{\cot 108^\circ}{\sqrt{1 + \cot^{2} 108^\circ}}$
- $\frac{1}{\sec 108^\circ}$
- $\pm\frac{\sqrt{\csc^{2} 108^\circ – 1} }{\csc 108^\circ}$
As the cosine function is the reciprocal of the secant function, 1 / sec 108° = cos108°.
In the next part we discuss the trigonometric significance of cos108°, and there you can also learn what the search calculations form in the sidebar is used for.
What is cos 108°?
In a circle with the radius r, the horizontal axis x, and the vertical axis y, 108 degrees is the angle formed by the two sides x and r; r moving counterclockwise is the positive angle.
As detailed in the unit-circle definition on our homepage, assumed r = 1, in the intersection of the point (x,y) and the circle, x = cos 108°.
Note that you can locate many terms including the cosine108° value using the search form. On mobile devices you can find it by scrolling down. Enter, for instance, value of cos108°.
Along the same lines, using the aforementioned form, can you look up terms such as cos 108° value, cos 108, cos108° value and what is the cos of 108 degrees, just to name a few.
Given the periodic property of cosine of 108°, to determine the cosine of an angle > 360°, e.g. 828°, calculate cos 828° as cos (828 Mod 360)° = cosine of 108°, or look it up with our form.
Conclusion
The frequently asked questions in the context include what is cos 108 degrees and what is the cos of 108 degrees for example; reading our content they are no-brainers.
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– Article written by Mark, last updated on February 17th, 2017