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Mathematics 8 Online
OpenStudy (anonymous):

Trig Help!!

OpenStudy (anonymous):

like what?

OpenStudy (anonymous):

What values for \[\theta(o \le \theta \le2\pi)\] \[4\cos \theta +1=2\] &

OpenStudy (anonymous):

\[\cos \theta -\tan \theta \cos \theta =0\] I have to satisfy the equations

OpenStudy (anonymous):

first one tells you \(\cos(\theta)=\frac{1}{4}\)

OpenStudy (anonymous):

second one tells you \(\tan(\theta)=1\)

OpenStudy (anonymous):

That's not an option for the first. My choices are \[\frac{ 2 \pi }{ 3 }, \frac{ 4\pi }{ 3 }\] \[\frac{ \pi }{ 6 } , \frac{ 5\pi }{ 6 }\] \[\frac{ 7\pi }{ 6 }, \frac{ 11\pi }{ 6 }\] \[\frac{ \pi }{ 3 }, \frac{ 6\pi }{ 3 }\]

OpenStudy (anonymous):

Second equation my choices are \[0, \frac{ \pi }{ 4 }, \pi , \frac{ 5\pi }{ 4 }\] \[\frac{ \pi }{ 4 }, \frac{ 5pi }{ 4 }\] \[\frac{ \pi }{ 2 }, \frac{ 3\pi }{ 4 }, \frac{ 3\pi }{ 2 }, \frac{ 7\pi }{ 4 }\] \[\frac{ \pi }{ 2 }, \frac{ 7\pi }{ 6 }, \frac{ 3\pi }{ 2 }, \frac{ 11\pi }{ 6 }\]

OpenStudy (anonymous):

must be some mistake, because it is not likely that the cosine of any of those number is \(\frac{1}{4}\)

OpenStudy (anonymous):

the original question before the equations is "what values for \[\theta(\theta \le \theta \le 2\pi )\] satisfy the equation"

OpenStudy (anonymous):

Any clues at all?

OpenStudy (anonymous):

\[4\cos (\theta) +1=2\]\[4\cos(\theta)=1\] \[\cos(\theta)=\frac{1}{4}\] was there a typo there in the question ?

OpenStudy (anonymous):

This is a screen shot of the equations and answers.

OpenStudy (anonymous):

oooh i thought you said "simultaneously" like they both had to be true two different questions !

OpenStudy (anonymous):

also the first one is completely different

OpenStudy (anonymous):

Ha no.

OpenStudy (anonymous):

and how so?

OpenStudy (anonymous):

\[4\cos(x)+1=2\cos(x)\] not \(2\)

OpenStudy (anonymous):

\[4\cos(x)+1=2\cos(x)\iff \cos(x)=-\frac{1}{2}\] by algebra then trig to get \(x=\frac{2\pi}{3}\) or \(x=\frac{4\pi}{3}\)

OpenStudy (anonymous):

ok and ya sorry typo on the first one. so how would you figure the second?

OpenStudy (anonymous):

any steps clear or not clear in that one?

OpenStudy (anonymous):

No I got that one I see how you got the answers

OpenStudy (anonymous):

second one factor and start with \[\cos(x)(1-\tan(x))=0\] so \[\cos(x)=0\] or \[\tan(x)=1\] then solve those

OpenStudy (anonymous):

Okay, just imput the numbers given for x and they should equal 0?

OpenStudy (anonymous):

that is one way or you could know that \(\cos(\frac{\pi}{2})=0\) and \(\cos(\frac{3\pi}{2})=0\)

OpenStudy (anonymous):

and also see if you know where \(\tan(x)=1\)

OpenStudy (anonymous):

okay

OpenStudy (anonymous):

ok I must be really dumb or over tired or something because I am not getting any correct answers... @satellite73

OpenStudy (anonymous):

figured it out thanks for the help!

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