anonymous
  • anonymous
Help with trigonometry identities please! Simplify: a) cos(180º +x) + cos(180º - x) b) cos(7pi/126º)cos(36º/5)+sin(7pi/126º)sin(36º/5)
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
jamiebookeater
  • jamiebookeater
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
amistre64
  • amistre64
cos(a+b) - cos(a-b): cos^2(a) - sin^2(a) + cos^2(a) + sin^2(a) 2cos^2(a) 2cos^2(180) ; cos(180) = -1 2(-1^2) = 2(1) = 2
amistre64
  • amistre64
\[7\pi/126^O\] ????
amistre64
  • amistre64
if anything that would equal 7pi(180)/126pi ... but ive never seen anything written like that before.

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
this is the equation:
1 Attachment
amistre64
  • amistre64
well, its a cos(a-b) construct, but i dunno about those digits
amistre64
  • amistre64
if you convert the degrees to radians, then I spoose you can have a radian measure without a pi in it.... but its just unnatural :)
anonymous
  • anonymous
ok..thanks for the help on the first one
amistre64
  • amistre64
7pi = 180 degrees, lets substitute that in instead
amistre64
  • amistre64
cos(180/126)cos(36/5) + sin(180/126º)sin(36/5)
amistre64
  • amistre64
then cos(180/126 - 36/5) is your angle....
amistre64
  • amistre64
add the fractions and simplify... right?
amistre64
  • amistre64
3636 ----- 630
amistre64
  • amistre64
602/105...whats our remainder?
anonymous
  • anonymous
did u already multiply the fraction by cos? im confused, sorry :S
amistre64
  • amistre64
5 + (77/105)
amistre64
  • amistre64
you dont need to do that :) you just need to find the angle of the cos: cos(a - b); find a - b
amistre64
  • amistre64
108(5) 36(126) ------ - -------- 126(5) 126(5)
amistre64
  • amistre64
180(5) 36(126) ------ - -------- 126(5) 126(5) arghh!!..typoed it lol
amistre64
  • amistre64
3636 cos of ----- is what I get 630
amistre64
  • amistre64
-3636 ------ you gotta catch this stuff, cause I dont always ;) 630
anonymous
  • anonymous
Amistre please help :'(
amistre64
  • amistre64
that looked alot better in my head lol
amistre64
  • amistre64
loco..... give me a sec; im on break ;)
anonymous
  • anonymous
ok
anonymous
  • anonymous
im not about to catch anything lol. i am very confused by trig in general..im about to post a question on trig identities...could u maybe help me through those when i post it? u seem like u know what ur doing :)
amistre64
  • amistre64
its a farse, I no nutheeenng!!!
anonymous
  • anonymous
he does. he know his stuff :)
anonymous
  • anonymous
ur a superhero for a reason :)
amistre64
  • amistre64
pfftt!!!.....super hero, now I gotta wear tights, and that aint a pretty picture ;)
amistre64
  • amistre64
I get an angle of -5.77 degrees when we do all that.
amistre64
  • amistre64
that is if its even right lol
amistre64
  • amistre64
the cos of that angle = .9949 and thats the best I got fer ya on that one....right or wrong ;)
anonymous
  • anonymous
r u solving the whole question btw? i just need to simplify..
amistre64
  • amistre64
I solved it for the angle; andle = 5 + (77/105) and for the value of the cosine of that angle :=: .9949 how to simplify it is beyond me :)
anonymous
  • anonymous
:'( ok. that's better than no answer at least!
amistre64
  • amistre64
well, -5 and 77/105ths.... but yeah :) ..good luck with it; if anything, get it wrong and move ahead :)

Looking for something else?

Not the answer you are looking for? Search for more explanations.