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Find the value of : sin 47 (degrees) + sin 61 (degrees)  sin 11 (degrees)  sin 25 (degrees)
 one year ago
 one year ago
Find the value of : sin 47 (degrees) + sin 61 (degrees)  sin 11 (degrees)  sin 25 (degrees)
 one year ago
 one year ago

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1on1Best ResponseYou've already chosen the best response.0
set the calculator to degrees and start pressing buttons
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
lol @1on1 , that's a shortcut but I do want to do that without *calculator*
 one year ago

1on1Best ResponseYou've already chosen the best response.0
Sorry, that will require much more thought from me !
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
No problem! @sasogeek any suggestions, if no then I have only 1 .
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
Not suggestion but an idea infact.
 one year ago

sasogeekBest ResponseYou've already chosen the best response.0
use the calculator to find their actual values and do normal addition... that's if u want to do some work... if not, u may use the calculator to find the whole answer.
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
hmn quite hard if calculator is not allowed.
 one year ago

sasogeekBest ResponseYou've already chosen the best response.0
earlier i thought it was sin(A+B)sin(AB) sort of question but it's not, direct solution with the calculator is the way forward :) unless u know those values off the top of ur head xD
 one year ago

sasogeekBest ResponseYou've already chosen the best response.0
i do not wish to confuse you, but you may want to read this, http://www.trans4mind.com/personal_development/mathematics/trigonometry/sumProductCosSin.htm#Sum_of_Sine_and_Cosine
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.1
@mathslover Do u knw the Value of Sin18 and cos36
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.1
SinA + SinB = 2Sin (A+B)/2 . Cos (AB)/2...Use this
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
@Yahoo! and @sasogeek this was my main idea.
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
Let me try again to find out the answer through the formula of sina + sinb
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
OK so if I remember the values of : cos 36 degrees and sin 18 degrees then I am getting cos 7 degrees.
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
cos Here is it how I did that : \[\large{\sin 47 + \sin 61 = 2 \sin 54 \cos 7 }\] ^that theta(s) are in degrees. similarly : \[\large{(\sin 11 + \sin 25) = ( 2\sin 18 \cos 7)}\] from the above we get : \(2\cos 7 ( \sin 54  \sin 18 )\) \(2\cos 7 ( 2\cos 36 \sin 18)\) \(4\cos 7 (\frac{\sqrt{5}+1}{4} \times \frac{\sqrt{5}1}{4})\) \(\cos 7\) That is it! Is it correct? @sasogeek @Yahoo!
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.1
Yup...thats wat i also Got
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.1
2Sin54.cos7  2sin18cos7 2cos7 ( sin54  sin18) sin54 = cos 36 2cos7(cos36  sin18) 2cos7( (sqrt5 + 1)/2  (sqrt51)/2) = cos7
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.1
Sorry 2cos7( (sqrt5 + 1)/4  (sqrt51)/4)
 one year ago

mathsloverBest ResponseYou've already chosen the best response.2
np, thanks a lot for your help yahoo.
 one year ago

Yahoo!Best ResponseYou've already chosen the best response.1
To..Be honest..U Did All the Hard Work..)
 one year ago
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