Why does sin80°csc80° equal 1?

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
10 replies · 8K views
CrossFit415
Messages
160
Reaction score
0
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
 
on Phys.org
And I also have trouble doing this...

Cos400° • sec40°= 1 I don't understand how they got one.
 
CrossFit415 said:
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?
 
CrossFit415 said:
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?
 
Replace csc80° with 1/sin? U
 
CrossFit415 said:
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 [tex]sin(80^o)\cdot\frac{1}{sin(80^o)}[/tex] ?
 
Thanks a lot for the help!
 
Mark44 said:
As far as the cosine is concerned, 400° is the same as what standard angle?

Same angle as 40°
 
HallsofIvy said:
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.