SOLUTION: find value of: cos(2π/7)+cos(4π/7)+cos(6π/7)
= cos(14pi/7 - 8pi/7) = cos( (14pi-8pi)/7 ) = cos(6pi/7) This will be useful to show that we have symmetry going on. Similar steps are applied to demonstrate cos(10pi/7) = cos(4pi/7) and …
SOLUTION: How would I find the exact value of sin (6pi) ? and cos ...
sin (6pi) ? and cos (-11pi/2) ? ** sin 6π Starting from zero, this means rotating thru π or180º 6 times counter-clockwise which ends at zero. So, sin 6π=0.. cos (-11pi/2) This means rotating …
How to prove that #cos^2((4pi)/7)-sin^2((3pi)/7)=cos((6pi)/7)
May 28, 2018 · #=cos((6pi)/7)=RHS# Answer link. Related questions. How do I determine the molecular shape of a molecule? ...
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Aug 10, 2015 · Find cos ((-3pi)/8) Ans: sqrt(2 - sqrt2)/2 Call cos ((-3pi)/8) = cos t cos 2t = cos ((-6pi)/8) = cos ((6pi)/8) = cos ((3pi)/4) = -sqrt2/2 Use the trig identity: cos ...
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Mar 2, 2018 · First, simplify the 2 factors --> #sin ((- 50pi)/3) = sin (- (2pi)/3 - (48pi)/3) = sin ((- 2pi)/3 - 16pi) =# ...
What is #2(cos(7/6pi) + isin(7/6pi))*8(cos(1/6pi) - Socratic
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#sum_(k=1)^5 cos(k(pi/11)) - Socratic
Oct 23, 2017 · LHS=cos^2 (pi /11) + cos^2((2 pi )/11 )+ cos^2 ((3 pi)/ 11) + cos^2(( 4 pi)/ 11) + cos^2(( 5 pi )/11) ) =1/2(2cos^2 (pi /11) + 2cos^2((2 pi )/11 )+ 2cos^2 ((3 pi)/ 11 ...
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May 23, 2018 · How do you use the ordered pairs on a unit circle to evaluate a trigonometric function of any angle
SOLUTION: Prove that: …
You can put this solution on YOUR website! Prove that: cos(2pi/7)+cos(4pi/7)+cos(8pi/7)= - 1/2