Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °
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Yeah,thanks you helped me a lot in this post.
Now put theta = 2A and you can re-arrange to get
and so on.
Is that what you wanted?
Quick question:are these formulas used to find half angle formulas?
Hi bob. I have derived the cosine's sum formula,and after trying a little i found the difference formulas too:),plus i know how to derive tangent's formula using sine and cosine
OK. Let me know how you get on.
Thanks for your help,now i'm going to try to derive the cosine formula(thanks again).
note EF = CB
The cosine formula is very similar. I'll leave it as an exercise.
hint AF = AB - FB
Sorry,I got confused with names of formulas(my mother-tongue isn't english )amd wrote wrong,I wanted to derive the compound angle formulas using trigonometry.
Yes, me too. All are acsii 43 so it's not that.
It's working for me, but only on its own!
The + sign won't parse for me.