If i know then how can we find (Wondering)(Thinking)(Itwasntme)

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- Jul 24th 2009, 03:19 AMjashansinghalhelp me out
If i know then how can we find (Wondering)(Thinking)(Itwasntme)

- Jul 24th 2009, 03:36 AMSENTINEL4
Maybe one way is that if you have sinx=y , where y is a number, find from the tables for which x you have y.

Then if you find x, find x/2 and from the tables again find sin(x/2) - Jul 24th 2009, 03:38 AMjashansinghal
If i know sin x = y from the trig table but i dont have sin (x/2), then????

- Jul 24th 2009, 03:42 AMpomp
If you know then you know , if you know you know , if you know then you know

- Jul 24th 2009, 03:47 AMSENTINEL4
- Jul 24th 2009, 03:48 AMjashansinghal
ok....

i know sin 45 = 1/sqrt 2

but i dont know sin 22.5

????? - Jul 24th 2009, 03:59 AMSENTINEL4
By using trig tables you should be able to find it.

- Jul 24th 2009, 04:00 AMMoo
Is there 22.5 in a trig table ? -_-

Note that since 45 is in the first quadrant, 45/2 is also in the first quadrant.

We know that

So

Let

Then

This is a quadratic equation. In your situation, we have :

Solve for T, by remembering it's positive (because it's a square)

And then take its square root, by remembering that it must be positive (because x/2 is in the first quadrant) - Jul 24th 2009, 04:00 AMpomp