how to find sin pi/8, cos pi/8 and tan pi/8

[kettles]

as the title says, how would i find their values !

[pi]

You will have to use sin(2x), cos(2x), etc. formulas, letting pi/4 = 2x (so you solve for sin(x), cos(x), whatever; where x = pi/8)

[Special At Specialist]

Yeah what pi said.

How you can tell is by converting to degrees. If it's divisible by 15 degrees, then you can use the addition/subtraction formulas. Otherwise, you need to use the double angle formulas.
In this case, pi/8 = 22.5 degrees, so the only option is to use the double angle formulas.

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