View Full Version : Trig functions, identities
CrossFit415
Mar5-11, 04:24 PM
I'm on mobile so I can't use regular symbols.
Sin80°csc80° = 1 why does this equal one? Is there multiplication involved here?
I know csc = 1/sin
CrossFit415
Mar5-11, 04:27 PM
And I also have trouble doing this...
Cos400° • sec40°= 1 I don't understand how they got one.
I'm on mobile so I can't use regular symbols.
Sin80°csc80° = 1 why does this equal one? Is there multiplication involved here?
I know csc = 1/sin
More precisely, csc(x) = 1/sin(x), so what can you replace csc(80°) by?
And I also have trouble doing this...
Cos400° • sec40°= 1 I don't understand how they got one.
As far as the cosine is concerned, 400° is the same as what standard angle?
CrossFit415
Mar5-11, 05:21 PM
Replace csc80° with 1/sin? U
Replace csc80° with 1/sin? U
No - replace csc80° with 1/sin80°.
Mentallic
Mar5-11, 05:57 PM
I'm on mobile so I can't use regular symbols.
Sin80°csc80° = 1 why does this equal one? Is there multiplication involved here?
I know csc = 1/sin
Yes, so what is sin(80^o)\cdot\frac{1}{sin(80^o)} ?
CrossFit415
Mar7-11, 03:30 AM
Thanks a lot for the help!
CrossFit415
Mar7-11, 03:40 AM
As far as the cosine is concerned, 400° is the same as what standard angle?
Same angle as 40°
HallsofIvy
Mar7-11, 05:14 AM
Yes, so cos(400)= cos(40). Now, what is sec(40) equal to?
CrossFit415
Mar10-11, 02:30 AM
Yes, so cos(400)= cos(40). Now, what is sec(40) equal to?
Cos is the same angle as 40° . sec = 1/cos40° and they cancel out to be 1.
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