How do you find the exact value of sin(2pi/5)?
2007-03-30 17:43:16 · 2 answers · asked by memory.less 1 in Science & Mathematics ➔ Mathematics
Hi,
Grab your handy-dandy calculator. Check the mode - be sure you are set on radians, not on degrees. Press the sine button, [sin].
Inside the parentheses, type in 2Pi/5) and press Enter. If your calculator works like mine, you will get .9510565163. (.9511)
If your calculator doesn't have a Pi button, press [sin] and type in sin(2*3.14/5). You will get .9509,which is just a little off. To be more exact, carry Pi out further than 3.14. sin(2*3.14159/5) is .9511.
I hope this helps!
2007-03-30 18:21:15 · answer #1 · answered by Pi R Squared 7 · 0⤊ 0⤋
You may not be able to find the exact value (it may not be rational), but you can use the series representation of the Sin to evaluate it. In this series, x= 2pi/5
Sin = x - x3/3! + x5/5! etc.
Expect to go out several terms before the terms left over become very small.
2007-03-31 01:04:29 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋