To calculate (without a calculator) construct right triangles with each angle
45 degrees is a 1-1-sqr2 right triangle. 1=opposite side=adjacent side
sum their squares to get the square of the hypotenuse = 2
take the square root of 2 = the hypotenuse length.
cosine of 45 degrees is adjacent side over hypotenuse = 1/sqr2 = sqr2/2 = about 1.414/2 = 0.707
secant 45 degrees = 1/cos45 = sqr2/1 = sqr2 = 1.414
sin45 = cos45 = 0.707
cosecant45 = 1/sin45 = 1.414
tan45 = opposite side over adjacent side = 1/1 = 1
cotan45 = tan45 = 1
60 degrees involves a 1-sqr3- 2 right triangle, with adjacent side=1, opposite side = sqr3 and
hypotenuse = 2
cos60=adjacent over hypotenuse = 1/2 = 0.5
sin60 = opposite side over hypotenuse = sqr3/2 = 1.732/2 = 0.866
sec 45 = 1/cos45 = 1//1/2 = 2
csc60 = 1/sin60 =2/sqr3
Those are standard right triangles, for 30, 45, 60, 90, 120, 135, 150, 180
all involving the same 1-sqr3-2 and 1-1-sqr2 right triangles, but with some negative signs between 90 and 180 degrees for tangent, cotangent, cosine, and secant. sines and cosecants are still positive in both quadrant I and II.
to get 5 degrees fiunctons you'd need a triple angle formula with 5 x3 =15 and a double angle formula for 15x2 =30
just google double angle formula and triple trigonometric formula