Solution :
The value of Cos 0 degrees is equal to 1.
Proof :
\(\angle\) A is made smaller and smaller in the right \(\Delta\) ABC till it becomes zero. As \(\angle\) A gets smaller and smaller the length of the side BC decreases. The point C gets closer to the point B and finally when \(\angle\) A becomes very close to 0 degrees, AC becomes almost the same as AB, and BC gets very close to 0.
By using trigonometric formula,
cos A = \(base\over hypotenuse\) = \(b\over h\) = \(AB\over AC\)
AC is nearly becoming same as AB.
cos A = \(AB\over AB\) = 1
Hence, \(cos 0^{\circ}\) = 1
