how do i evaluate using formulas? i did almost the entire thing, but i can't finish the problem because i don't know how to simplify it:
tan(-5/12pi)
i can get until this part:
= (-6pi/24)+(4pi/24) / 1-(-2pi/24)
sometimes it helps to "think" in degrees rather than radians, and then switch back.
e.g. (5/12)π = 75 degrees
so you want tan (-75)
You should know that tan(-A) = -tanA
so tan(-75)
= -tan75
= -tan(45+30)
= -(tan45 + tan30)/)1 - tan45tan30
= -(1 + 1/√3)/(1 - 1/√3)
multiply top and bottom by √3
= -(√3 + 1)/(√3 - 1)
so tan((-5/12)π) = -(√3+1)/(√3-1)