why does sin cosin doesn't go over 90 degrees
It does. Cosine 345 has a value.
The reason why the sine and cosine functions typically do not have values greater than 90 degrees is because they are defined in relation to a right triangle. In a right triangle, the largest angle is always 90 degrees.
The sine (sin) of an angle in a right triangle is defined as the ratio of the length of the side opposite the angle to the length of the hypotenuse. The cosine (cos) of an angle in a right triangle is defined as the ratio of the length of the adjacent side to the length of the hypotenuse.
In this context, the sine and cosine functions can only give meaningful values for angles between 0 and 90 degrees. Beyond 90 degrees, the angles would not correspond to any side lengths in a right triangle, and thus the definitions of sine and cosine would not apply directly.
However, it's worth noting that trigonometric functions can be extended beyond 90 degrees using the unit circle or more advanced mathematical concepts. For example, the cosine 345 can be calculated by using reference angles or trigonometric identities.