A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 3 years ago
Can someone help me please?
Rewrite with only sin x and cos x.
cos 2x + sin x
anonymous
 3 years ago
Can someone help me please? Rewrite with only sin x and cos x. cos 2x + sin x

This Question is Open

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Okay. So this stems from trigonometric identities and double angle formulas. Do you know any double angle formulas?

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Not really, no. Sorry

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0No prolem. A really good reference for all of these formulas would be this: (one minute.)

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0*No problem. Anyways, here's the webpage with pretty much every possible identity you can imagine for Trig. http://www.sosmath.com/trig/Trig5/trig5/trig5.html You'll notice that under the double angle formulas section, Cos(2x) has three different accompanying equations. Can I ask what math you're in right now, i'm assuming Precalc?

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0You are correct, I'm in precalc. And thanks for the link btw. That is awesome.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0\[\cos(2x) = \cos ^{2}(x)  \sin ^{2}(x)\]\[\cos(2x) = 2\cos ^{2}(x)1\]\[\cos(2x) = 1  2\sin ^{2}(x)\]

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0No problem. Okay, given these formulas, we can substitute cos(2x) for other things without double angles. Right now, we've got \[\cos(2x) + \sin(x)\], correct?

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0(Sorry for asking something you obviously know the answer to, just giving myself time to think LOL. I haven't done this in a while.)

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0No you're doing great. You're helping me way more than anyone has thus far. Take all the time you need I really appreciate your helping me out man.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0No worries. I'm a little confused about the vague instructions. While you can rewrite it with those terms, i'm wondering if it's acceptable to have only sine, only cosine, or whether cosine or sine squared is acceptable. After all, that is basically what these are. Guess every case might be worked out.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0If it helps, the possible answers are: 1 + 3 sin x 1 + 3 sin2x 1  2 sin2x + sin x 1 + 2 sin2x + sin x

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0The last 3 are (sin^2 x) btw

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Oh, lol, okay then. That's WAY simpler than what I was about to do. My bad, I was like, halftrying to solve a trig identity. So yeah, just take a look at the formulas I put up, and substitute them. From there it's super easy to see which one makes sense with the possible answers.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Don't try to solve anything, just see which substitution would get you closest to the answers given. It should be a single step.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0I think so. So the answer would just be 1  2 sin2x + sin x

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Exactly, but I have to say, don't be afraid of using the carat symbol (^) if you're ever writing something on a computer and can't put in a fancy superscript like: \[\sin ^{2}x\] to denote when a value is squared. People could very, very easily misread it as sin(2x) instead of sin^2(x), and that could mess up a whole problem.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Thanks for the tip and all your help. I can't thank you enough.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0No problem. Good luck with Precalc. I struggled a lot with it when I first learned it.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0(Heck, i'm still learning it, albeit different forms.)

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Haha. I guess it never really ends does it?

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0Nope. We're dumb forever. :P PS, I don't know if this would apply to you, but do you use flash cards to study?

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0sometimes. I guess it depends on what I am studying. If there are a lot of vocabulary words or something I will usually use flashcards.
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.