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anonymous
 one year ago
I need complete help..
Complete the identity.
Cos(a b)/cos a cos b
A. 1 + cot a cot b
B. Tan a tan b + cot b
C. 1 + tan a tan b
D. 1 + cot a tan b
anonymous
 one year ago
I need complete help.. Complete the identity. Cos(a b)/cos a cos b A. 1 + cot a cot b B. Tan a tan b + cot b C. 1 + tan a tan b D. 1 + cot a tan b

This Question is Closed

freckles
 one year ago
Best ResponseYou've already chosen the best response.1try expanding the cos(ab) part

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0How? I look at my textbook, but it isn't helping me understand more.

freckles
 one year ago
Best ResponseYou've already chosen the best response.1then separate the fraction after the expansion do some canceling and finally just a little rewriting

freckles
 one year ago
Best ResponseYou've already chosen the best response.1you don't know the difference identity for cosine?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0No. My textbook never showed or told me.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0It just gives me problems to do and then I take my test.

freckles
 one year ago
Best ResponseYou've already chosen the best response.1sin(xy)=sin(x)cos(y)sin(y)cos(x) sin(x+y)=sin(x)cos(y)+sin(y)cos(x) cos(x+y)=cos(x)cos(y)sin(x)sin(y) cos(xy)=cos(x)cos(y)+sin(x)sin(y) so you never seen these identities? that is odd

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Correct. I am working hard to learn.. But I am confused.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Can you help me a little better?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1can you tell me if you applied that identity yet?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Like, I am confused. I have done some sins, cos, and tans but not like this.

freckles
 one year ago
Best ResponseYou've already chosen the best response.1do you see the cos(ab) on top?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1do any of the identities I mentioned look like this on the left hand side?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1well can you apply that identity then...

freckles
 one year ago
Best ResponseYou've already chosen the best response.1like can you expand cos(ab)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0The expanding is the confusing part. Never done it.

freckles
 one year ago
Best ResponseYou've already chosen the best response.1so you don't see how cos(xy) looks exactly like cos(ab) except in the place of x we have a and in the place of y we have b?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1replace the x and y on the right hand side with a and b respectively

freckles
 one year ago
Best ResponseYou've already chosen the best response.1and you have expanded cos(ab)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Okay. Is that all I do?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1to expand cos(ab) yes for the question you have asked here at the top, no

freckles
 one year ago
Best ResponseYou've already chosen the best response.1I actually gave a few more steps above after the expansion

freckles
 one year ago
Best ResponseYou've already chosen the best response.1something about separating the fraction canceling stuff and rewriting a bit

freckles
 one year ago
Best ResponseYou've already chosen the best response.1can you show me what you have after rewriting \[\frac{\cos(ab)}{\cos(a)\cos(b)}\]

freckles
 one year ago
Best ResponseYou've already chosen the best response.1or show me what you have for the numerator please

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Cos(xy)= cos(x) cos (y) I am still somewhat confused

freckles
 one year ago
Best ResponseYou've already chosen the best response.1ok well it looks like you didn't use the identity I mentioned above

freckles
 one year ago
Best ResponseYou've already chosen the best response.1cos(xy)=cos(x)cos(y)+sin(x)sin(y)

freckles
 one year ago
Best ResponseYou've already chosen the best response.1dw:1444190564321:dw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Uhhh, ??? Sorry.. I have no clue. I have never done a problem like this. Cos(xy)

freckles
 one year ago
Best ResponseYou've already chosen the best response.1dw:1444190659448:dw

freckles
 one year ago
Best ResponseYou've already chosen the best response.1dw:1444190692534:dw

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

freckles
 one year ago
Best ResponseYou've already chosen the best response.1\[\frac{\cos(ab)}{\cos(a)\cos(b)}=\frac{\cos(a)\cos(b)+\sin(a)\sin(b)}{\cos(a)\cos(b)}\] write as two fractions (separate the fraction)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Okay. I am understanding a little more.

freckles
 one year ago
Best ResponseYou've already chosen the best response.1\[\frac{\cos(a) \cos(b)}{\cos(a) \cos(b)}=1\] and \[\frac{\sin(a) \sin(b)}{\cos(a) \cos(b)}=\frac{\sin(a)}{\cos(a)} \frac{\sin(b)}{\cos(b)}=...?\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0It equals... I have no clue. I am trying.

freckles
 one year ago
Best ResponseYou've already chosen the best response.1so you don't know what tan(x) equals in terms of sin(x) and cos(x)?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1then what does it equal?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1or did you mean sin(a)/cos(a)=tan(a) and sin(b)/cos(b)=tan(b)?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1ok great \[\frac{\cos(a) \cos(b)}{\cos(a) \cos(b)}=1\] while \[\frac{\sin(a) \sin(b)}{\cos(a) \cos(b)}=\frac{\sin(a)}{\cos(a)} \frac{\sin(b)}{\cos(b)}=\tan(a) \tan(b)\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I am on the right track?

freckles
 one year ago
Best ResponseYou've already chosen the best response.1yes that is what we got 1+tan(a)tan(b)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Yay! Thank you, thank you!
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