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tanjung
Group Title
Help...
Prove that sin36 degrees = sqrt[10  2*sqrt(5)]/4
 2 years ago
 2 years ago
tanjung Group Title
Help... Prove that sin36 degrees = sqrt[10  2*sqrt(5)]/4
 2 years ago
 2 years ago

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micahwood50 Group TitleBest ResponseYou've already chosen the best response.0
HINT: 180º/5 = 36º
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
next, what's formula using i do
 2 years ago

micahwood50 Group TitleBest ResponseYou've already chosen the best response.0
Seems like it won't help. Try this, using the formula sin (a + b) = cosa sinb + cosb sin a sin36º = 2 sin18º cos18º = 2 cos72º sin72º
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
ok, i know that formula.. but i think we get the new problem... because sin/cos 18 or sin/cos 72 not eassy to get.. it's very difficul, right ?
 2 years ago

micahwood50 Group TitleBest ResponseYou've already chosen the best response.0
It seems so. Bump your question to get more helps. Maybe someone can help you with this.
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
ok, thanks...
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
@cwrw238 , @experimentX , @estudier , @Hero , @Zarkon , @sauravshakya , @all... help me please, how to get it
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
any idea guys ?
 2 years ago

ajprincess Group TitleBest ResponseYou've already chosen the best response.1
dw:1350231015827:dwdw:1350231152168:dw Use quadratic formula dw:1350231253477:dw dw:1350231349862:dw
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
@ajprincess try thisdw:1350231460480:dw
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
ok, i get dw:1350231717622:dw
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
upss. sorry, divided 8
 2 years ago

ajprincess Group TitleBest ResponseYou've already chosen the best response.1
dw:1350231971343:dwdw:1350232035700:dw
 2 years ago

ajprincess Group TitleBest ResponseYou've already chosen the best response.1
@experimentX I tried bt it is a bit complex. cos sin3x=sin108.
 2 years ago

ajprincess Group TitleBest ResponseYou've already chosen the best response.1
Getting it @tanjung?
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
this should be simpler ... sin(3x) = sin(2x)
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
not yet, what should i do after that
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
since this is just double angle and triple angle ... change everything back to sin ... and remove all roots and try to factorize it.
 2 years ago

ajprincess Group TitleBest ResponseYou've already chosen the best response.1
dw:1350232254804:dw
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
so, just take positive sign in sqrt ?
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
i know that + it means there are two number here. what about u for it
 2 years ago

mukushla Group TitleBest ResponseYou've already chosen the best response.0
with positive sign u have sin 36>1 thats impossible
 2 years ago

ajprincess Group TitleBest ResponseYou've already chosen the best response.1
dw:1350233305717:dw
 2 years ago

tanjung Group TitleBest ResponseYou've already chosen the best response.0
oh yea, i understand now... thank u very much for ur help , @ajprincess and @mukushla
 2 years ago
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