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# C3 Addition Formulae Help Watch

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2Sin(x)=Cos(x-45)

Thanks
2. Use the addition formulae on cos(x-45)
evaluate cos45 and sin45 and rearrange.
3. expand the RHS. put in the value of cos 45° and sin 45°.

rearrange to get all the sinx on the left & the cosx on the right....*
4. (Original post by NotNotBatman)
Use the addition formulae on cos(x-45)
evaluate cos45 and sin45 and rearrange.
I've tried that method but I keep getting the same answer which isn't correct. I get x= 61.325, is this what you get?
5. (Original post by gtmharnett)
I've tried that method but I keep getting the same answer which isn't correct. I get x= 61.325, is this what you get?
I got 28.7. Post your full working and we'll find where you're going wrong.
6. (Original post by gtmharnett)
I've tried that method but I keep getting the same answer which isn't correct. I get x= 61.325, is this what you get?
No, show some more working.

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