Number 11 in the attached document.

I don't know how to do it .. I can't figure out what i'm supposed to do. Help please

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- Oct 22nd 2012, 06:28 PMBenja303Trigonometry cosine and sine rule
Number 11 in the attached document.

I don't know how to do it .. I can't figure out what i'm supposed to do. Help please - Oct 22nd 2012, 06:37 PMHallsofIvyRe: Trigonometry cosine and sine rule
So you only want people who have Microsoft Word to respond?

- Oct 22nd 2012, 06:39 PMBenja303Re: Trigonometry cosine and sine rule
Yes son.

- Oct 24th 2012, 09:31 AMStefanTMRe: Trigonometry cosine and sine rule
Hi,

A=45°

B=60°

=> C=75°

You have to use for the both questions the sin-Formula:

i) sinA/a =sinB/b => sin45°/a=sin60°/b => (sin45°)^2/a^2=(sin60°)/b^2

you have to introduce the values for sin45° and sin60° and to transform the expression

ii) The solution is analog

to use: sin75°= cos15°; cos(2x)=2*cos(x))^2 -1 =>cos(x) =root((1+ cos2x)/2) => cos15°=root((2+root(3))/2) = 1/2*root(2*(1+ root(3))^2)= (1+root(3))/root(2),

=> sin75°= (1+root(3))/root(2)