If the sin 90° = 1, then what is the value of cos 0°?

For sine, the angles with whole values would be 90 degrees and 270 degrees, having a value of 1 and - 1 respectively. Similarly for the cosine function, the only angles with a whole number value would be 0 degrees and 180 degrees, with the values of 1 and - 1 respectively.

From that, cos 0 degrees = 1.

Cos 0° = 1 ...