saifoo.khan
  • saifoo.khan
Easy trig problem below:
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.
schrodinger
  • schrodinger
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
?
saifoo.khan
  • saifoo.khan
\[\frac{3A}{sinA} + \frac{\cos3A}{\cos A}≡ 4 \cos 2A\]
anonymous
  • anonymous
cos(3A) = cos(2A+A) =4 cos³ A - 3 cos A

Looking for something else?

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

More answers

anonymous
  • anonymous
taking the LCM and then using 2 sinA * cos A= sin 2A
anonymous
  • anonymous
and cos 2A= cos^2 2A -1
saifoo.khan
  • saifoo.khan
I'm not sure about your working but i completed till here: \[\frac{\cos A \sin 3A + \cos 3A \sin A}{\sin A \cos A}\]
saifoo.khan
  • saifoo.khan
Then: \[\frac{\sin(A+3A)}{\sin A \cos A}\]idk what to do after this..
saifoo.khan
  • saifoo.khan
@jasonxx ?
anonymous
  • anonymous
well, i guess expand everything
zepdrix
  • zepdrix
\[\frac{\sin(4A)}{\frac{1}{2}\sin(2A)}\] This the next step? :) hmm fun problem.
zepdrix
  • zepdrix
\[\frac{4\sin(2A) \cos(2A)}{\sin(2A)}\] \[=4\cos(2A)\] Something like that... :D Yayyy team!
saifoo.khan
  • saifoo.khan
HOW? HOW? HOW?
anonymous
  • anonymous
sin(4A)=sin(2* 2A)
zepdrix
  • zepdrix
Oh like say what each step that's being performed? :D
saifoo.khan
  • saifoo.khan
Last 3 steps, yes sir. @zepdrix ;D
anonymous
  • anonymous
and sin (2*2A) is like sin (2* X)= 2*2 sin (2A)cos(2A)
zepdrix
  • zepdrix
Hmm so we're taking advantage of Sine's Double Angle Formula, On top, in one direction, on the bottom in the other direction. Yah looks like Jason has the right idea also ^^
anonymous
  • anonymous
:)) thanks @zepdrix
saifoo.khan
  • saifoo.khan
I have this general formula with me: sin2A = 2sinAcosA But how did you guys converted sin4A into this?
anonymous
  • anonymous
Let's say A=X then its gona be sin (2X), now X=2A therefore its gona be the conversion mentioned above
saifoo.khan
  • saifoo.khan
I think i got it now. Thanks @jasonxx and @zepdrix . :)
anonymous
  • anonymous
:) keep rockin
zepdrix
  • zepdrix
Oh sorry. I wasn't going into much detail because I thought you were testing us :) lol
saifoo.khan
  • saifoo.khan
Lol. No. this was the last problem of 26. i had the answers but wasn't getting the last step!
saifoo.khan
  • saifoo.khan
@zepdrix Where did the 1/2 in your second last step go? D:
zepdrix
  • zepdrix
So we're dividing by a fraction, let's fix that a sec. \[\frac{\sin(4A)}{\frac{1}{2}\sin(2A)} \quad = \quad \frac{2\sin(4A)}{\sin(2A)}\] Then we apply the Sine Double Angle Formula to the top part.\[\frac{2\sin(2\cdot 2A)}{\sin(2A)} \quad = \quad \frac{2\cdot 2 \sin(2A)\cos(2A)}{\sin(2A)}\]
saifoo.khan
  • saifoo.khan
Oh! Now it makes perfect sense to me!

Looking for something else?

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