trignometric simplify

Find: sin(arccos(3/5))

Find the exact value of csc105 degrees

Simplify: sin (x+y) - sin(x-y)

Prove that: sin2x/cotx = 1-cos2x

Find the exact value of sin(x+ pi/3)

I know thats a lot but any help would be amazing!!! I'm awful at this!!

btw how do you make the pi symbol on here??j

Hello,

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Originally Posted by antz215

Find: sin(arccos(3/5))

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$\displaystyle \sin(\arccos(3/5))=\pm \sqrt{1-(3/5)^2}$ (see where arccos 3/5 lies and conclude about the sign of the sine)

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Find the exact value of csc105 degrees

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Dunno.. have to find out what csc is...

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Simplify: sin (x+y) - sin(x-y)

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$\displaystyle \sin(x+y)=\sin(x)\cos(y)+\cos(x)\sin(y)$

$\displaystyle \sin(x-y)=\sin(x)\cos(-y)+\cos(x)\sin(-y)$

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Prove that: sin2x/cotx = 1-cos2x

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$\displaystyle \cot x=\frac{\cos x}{\sin x}$

$\displaystyle \sin 2x=2 \cos x \sin x$

$\displaystyle \Longrightarrow \frac{\sin 2x}{cot x}=2 \sin^2(x)=\dots$

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Find the exact value of sin(x+ pi/3)

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Use the formula $\displaystyle \sin(x+y)=\sin(x)\cos(y)+\cos(x)\sin(y)$

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btw how do you make the pi symbol on here??j

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[tex]\pi[/tex] (Wink)

thank you! most of that made sense to me, but what didnt wasnt your fault!

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Originally Posted by antz215

thank you! most of that made sense to me, but what didnt wasnt your fault!

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I can try to explain, as far as my knowledge allows me :)