RADIANS
π radians = 180 degreesBasic trig function 2: The graph of y = cos x is a curve that looks just like the sine curve except it
crosses the y-axis at (0, 1) because cos 0 = 1, falls to cross the x-axis at because cos
and continues on down to its floor at (π, –1) because cos π = –1:
Basic trig function 3: The graph of y = tan x looks like this: