Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ ¹ ² ³ °
 

You are not logged in. #2 20130214 22:08:44
Re: Sum and difference of sine and cosinehi {7/3} Funny the + sign won't work in Latex?? adding gives: If you put P = A +B and Q = AB, you get: The others are derived in a similar way. Bob Last edited by bob bundy (20130214 22:22:38) You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei #3 20130214 22:15:28
Re: Sum and difference of sine and cosineHi Bob The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #5 20130214 22:19:12
Re: Sum and difference of sine and cosineHmm... weird! It's working for me, but only on its own! Last edited by anonimnystefy (20130214 22:21:16) The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #7 20130214 22:30:50
Re: Sum and difference of sine and cosineHi; In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #8 20130214 23:29:37
Re: Sum and difference of sine and cosineSorry,I got confused with names of formulas(my mothertongue isn't english )amd wrote wrong,I wanted to derive the compound angle formulas using trigonometry. There are 10 kinds of people in the world,people who understand binary and people who don't. #9 20130215 00:44:52
Re: Sum and difference of sine and cosinehi {7/3} note EF = CB The cosine formula is very similar. I'll leave it as an exercise. hint AF = AB  FB Bob Last edited by bob bundy (20130215 01:06:40) You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei #12 20130215 12:03:29
Re: Sum and difference of sine and cosineHi 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 There are 10 kinds of people in the world,people who understand binary and people who don't. #15 20130215 22:00:26
Re: Sum and difference of sine and cosinehi Now put theta = 2A and you can rearrange to get and so on. Is that what you wanted? Bob You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei #17 20130216 00:10:14
Re: Sum and difference of sine and cosineYou're welcome. Last edited by bob bundy (20130216 00:14:05) You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei 