Question

Find the value of cos 765°​

Answer 1

Answer:

I hhave solved the question in the above image.

I hope it helps.

Answer 2

Given:  

A trigonometric function cos( 765° ).  

To Find:  

The value of the above function.  

Solution:  

The given problem can be solved using the concepts of trigonometry.  

1. The given trigonometric term is Cos( 4620°).  

2. According to the properties of trigonometry,  

=> Cos ( 360 + x ) = Cosx.  

3. Using the property mentioned above we can find the value of Sin( 3660°),  

=> Cos(765°) = Cos(360 + 405) = Cos(405°),  

=> Cos(405°) = Cos360+45) = Cos(45°),    

=> Cos(45°).  

4. The value of Cos(45°) is,

=> Cos(45°) = 1/√2

Hence, the value of Cos(765°) is 1/√2.