cos 13 pi = ?
cos 13π
= cos( 4(2π) + π) , 13π is 4 rotations + π
= cosπ
= -1
cos13pi
= cos 13pi*180/pi
=cos2340degree
= cos(7*360-180)
= cos(180degree)
= -1
hope u understood:)
To find the value of cos 13π, you can use the unit circle or a calculator. Here's how you can do it:
Using the unit circle:
1. Draw a circle with a radius of 1 and mark the points at the angles on the unit circle.
2. π radians is equivalent to 180 degrees. So, 13π radians can be converted into 13π * 180/π = 2340 degrees.
3. Locate the point on the unit circle corresponding to 2340 degrees.
4. Now, look at the x-coordinate of that point, which represents the cosine value.
5. In this case, cos 13π = cos 2340 degrees = x-coordinate of the point on the unit circle at 2340 degrees.
Using a calculator:
1. Most calculators have a built-in cosine function.
2. Input 13π into your calculator using the appropriate keys or functions (consult your calculator manual if needed).
3. Press the equals (=) button to find the value of cos 13π.
Regardless of the method you choose, you will find that cos 13π equals 1.