Posted by **Luis** on Sunday, March 17, 2013 at 5:11pm.

How do I find the exact value of sin (pi/24)?

- trig -
**Steve**, Sunday, March 17, 2013 at 5:24pm
sin π/6 = 1/2

cos π/6 = √3/2

sin(x/2) = √(1-cosx) / 2

cos(x/2) = √(1+cosx) / 2

apply the half-angle formula twice to get

sin π/24 = 1/2 √(2-√(2+√3))

- trig -
**Luis**, Sunday, March 17, 2013 at 5:36pm
I am not under standing could you show me ? to tell me ?

- trig -
**Luis**, Sunday, March 17, 2013 at 5:40pm
I applied the half angle formula for sin and I got the square root of 2 minus the square root of 3 divided by 2 . and for cos I got thesqurof 2 plus thesqr of3divided by 2 .

- trig -
**Luis**, Sunday, March 17, 2013 at 5:43pm
I really need help . I find this hard Steve .

- trig -
**Luis**, Sunday, March 17, 2013 at 5:51pm
Do I subtract ?

- trig -
**Steve**, Monday, March 18, 2013 at 9:50am
sin π/6 = 1/2

cos π/6 = √3/2

so,

cos π/12 = √(1+√3/2) / 2

sin π/24 = √(1-cos π/12) / 2

= 1/2 √(1 - (√(1+√3/2) / 2))

= 1/2√2 √(2 - √(1+√3/2))

= 1/4 √(2√2 - √(1+√3))

...

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