A community for students.
Here's the question you clicked on:
 0 viewing
chels
 5 years ago
sin(2x)cos(5x) + cos(2x)sin(5x)
use identities to simplify
chels
 5 years ago
sin(2x)cos(5x) + cos(2x)sin(5x) use identities to simplify

This Question is Closed

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0remember sin(z+y)=sinzcosy+sinycosz where in this case z=2x and y=5x

chels
 5 years ago
Best ResponseYou've already chosen the best response.0this is so confusing.. :(

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0do you know the identity sin(z+y)=sinzcosy+sinycosz

chels
 5 years ago
Best ResponseYou've already chosen the best response.0but i don't understand how it's used in this question because sin and cos are being multiplied together.

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0ok what if you let z=2x and y=5x what would you have?

chels
 5 years ago
Best ResponseYou've already chosen the best response.0i understand how to use the identity, i'm just confused as to where it's being used

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0ok we have [sin(2x)][cos(5x)]+[cos(2x)][sin(2x)]=[sin(z)][cos(y)]+[cos(y)][sin(z)]=sin(y+z) where y=2x and z=5x so this =sin(2x+5x)=sin(7x)

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0oops i wrote the samething twice and that post

chels
 5 years ago
Best ResponseYou've already chosen the best response.0ohhh my gosh. i get it now

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0ok good i don't have to write it over correctly then?

chels
 5 years ago
Best ResponseYou've already chosen the best response.0no, that is good 1 / 1cos(x) + 1 / 1 + cos(x)

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0i assume that (1cosx) and (1+cosx) are in the denominator right?

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0combine those fractions

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0numerator=(1+cosx)+(1cosx)=2 and denominator=1(cosx)^2=(sinx)^2

chels
 5 years ago
Best ResponseYou've already chosen the best response.0i got a denominator of 1cos(x)1+cos(x)

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0(1cosx)(1+cosx) use foil here

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0or you could use the fact that (ab)(a+b)=a^2b^2

chels
 5 years ago
Best ResponseYou've already chosen the best response.0we haven't learned that one, but i'll note it

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0thats an algebra thing it should had been algebra you learned that not trig

chels
 5 years ago
Best ResponseYou've already chosen the best response.0hmm, i don't remember it thankyou though.

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0(x3)(x+3)=x^29 and (x5)(x+5)=x^225 and so on....

chels
 5 years ago
Best ResponseYou've already chosen the best response.0\[\tan(\pi/5) + \tan(\pi/10) = numerator. 1  \tan(\pi/5)\tan(\pi/10)\]

chels
 5 years ago
Best ResponseYou've already chosen the best response.0sorry. let me rewrite that

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0what you got the one before this one?

chels
 5 years ago
Best ResponseYou've already chosen the best response.0numerator = tan(pi/5) + tan(pi/10) denominator = 1  tan(pi/5)tan(pi/10)

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0Do you remember the idenity tan(x+y)=[tanx+tany]/[1tanxtany]

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.0ok if you want more help, i'm gonna be away from my computer so people will notice you you might want to start a new thread k? if you like me become a fan
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.