A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 one year ago
Trig/ Pre Cal/ identities Am I on the right path? Please do not give answer but guide me. Thank you.
cos(x  y)  cos(x+y) = 2sin x siny
Is cos(xy) like
cos(aB) = cos a cos B + sin a sin B
anonymous
 one year ago
Trig/ Pre Cal/ identities Am I on the right path? Please do not give answer but guide me. Thank you. cos(x  y)  cos(x+y) = 2sin x siny Is cos(xy) like cos(aB) = cos a cos B + sin a sin B

This Question is Closed

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0cos(xy) like cos(aB) = cos a cos B + sin a sin B

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0just plug x and y into a and b

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Ok, this does not seem to work. cos x *cos y + sin y *sin y  cos x * cos y  sin x * sin y = 2sin x 2 sin y Should be 2sin x sin y. Am I skipping something?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0cos(x+y) is not like cos(xy)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0cos(x+y) = cos x cos y  sin x sin y

zepdrix
 one year ago
Best ResponseYou've already chosen the best response.1yah your angle sum and different expansions look correct nixy :) do you see the next step after that?

zepdrix
 one year ago
Best ResponseYou've already chosen the best response.1oh oh oh, i think you simply forgot to distribute the negative.

zepdrix
 one year ago
Best ResponseYou've already chosen the best response.1\[\Large\rm \cos(xy)\color{red}{}\cos(x+y)\]\[\Large\rm =\cos x \cos y+ \sin x \sin y \color{red}{}(\cos x \cos y \sin x \sin y)\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Ah ok I see. man it was right in front of me. The way you put it made it clearer lol

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Thanks @zepdrix and @Thesn1
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.