Trig quadrant Question

212
0
Solve: secx=-5.2, 0≤x≤2π

I'm getting 2 answers:
1.76, 4.52

The answer key is telling me there is only one
1.76

How do I only get 1 answer from this?

Thanks,
 
212
0
Evaluate: cot4.47

I'm getting .23 when i plug in: tan(1/4.47)

but the answer key says .25
am I doing something wrong?

thanks
 
1. [tex] \sec x = -5.2, \; 0\leq x\leq 2\pi [/tex]

[tex] \frac{1}{\cos x} = - 5.2 [/tex]

[tex] \cos x = -\frac{1}{5.2} = [/tex]

[tex] \arccos(\cos x) = 1.76 [/tex]

[tex] x = 1.76 [/tex]


2. [tex] \cot 4.47 = \frac{1}{\tan 4.47}[/tex] not [tex] \tan(\frac{1}{4.47}) [/tex]
 
212
0
thanks, I see what I did wrong for #2

but, why doesnt #1 have 2 answers?
 
Because the second answer is in quadrant 4, where cos is positive.
 
No, it's in the 3rd quadrant. There should be 2 solutions.
 

VietDao29

Homework Helper
1,417
1
Yes, there should be 2 answers. Cheers. :)
 
212
0
Alright
Thanks everyone
 

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