Ask your own question, for FREE!
Mathematics 18 Online
OpenStudy (studygurl14):

Help Please?! Medal

OpenStudy (studygurl14):

OpenStudy (studygurl14):

@TheSmartOne @jim_thompson5910 @SolomonZelman

OpenStudy (studygurl14):

@TheSmartOne @Mertsj @jim_thompson5910

OpenStudy (mertsj):

Factor out tan(x)

OpenStudy (studygurl14):

Oh, thanks! I'll try that

OpenStudy (mertsj):

yw

OpenStudy (studygurl14):

@Mertsj I'm stuck. I got this: tan x (sec x -2) = 0 tan x = 0 x = 0 sec x - 2 = 0 sec x = 2 ?

TheSmartOne (thesmartone):

I don't know anything about this :/ Sorry..

OpenStudy (freckles):

\[\tan(x)=0 \\ \cos(x)=\frac{1}{2}\]

OpenStudy (freckles):

are the equations you have to solve

OpenStudy (misty1212):

if \(\sec(x)=2\) then \(\cos(x)=\frac{1}{2}\)

OpenStudy (freckles):

and actually we can just say solve sin(x)=0 and solve cos(x)=1/2

OpenStudy (misty1212):

all your choices have \[0+k\pi\] from the \(\tan(x)=0\)

OpenStudy (studygurl14):

oh, right. thanks. don't know where my brain is

OpenStudy (jhannybean):

Correction: \[\tan(x) = 0 \implies x =\tan^{-1}(0)\]

OpenStudy (studygurl14):

x = 60 then...which is pi/3 in radians

OpenStudy (freckles):

also your choices are weird

OpenStudy (jhannybean):

You had written \[\tan(x) = 0\]\[x=0\]

OpenStudy (studygurl14):

Would the answer be B or D?

OpenStudy (freckles):

none of your choices make any sense one of your choices are close

OpenStudy (freckles):

but it is still not correct

OpenStudy (jhannybean):

Ok first off, what is the first value when \(x =\tan^{-1}(0)\)?

OpenStudy (studygurl14):

0 ^

OpenStudy (jhannybean):

And what are your domain restrictions? \([0,2\pi)\)?

OpenStudy (studygurl14):

I don't think there are any? ^

OpenStudy (mertsj):

If tan x = 0 then x is 0 or pi If sec x = 2 then cos x = 1/2 and x = pi/3 or 5pi/3

OpenStudy (studygurl14):

This all makes some sense to me, bu none of it is in the answer choices...ugh

OpenStudy (freckles):

hint: cos(x) is even so you could say cos(x)=cos(-x) but none of your choices will work

OpenStudy (freckles):

because k can't be irrational and an integer at the same time

OpenStudy (jhannybean):

Yes, there is a correct answer choice in that bunch

OpenStudy (studygurl14):

since x = pi/3, would x also work for any value that was (pi k)/3 ???

OpenStudy (studygurl14):

k equaling 1, 2, 3 , etc?

OpenStudy (jhannybean):

you're on the right track.

OpenStudy (studygurl14):

That's why I was thinking B or D ^

OpenStudy (freckles):

there is not a correct choice ...

OpenStudy (anonymous):

You know, only one of the given solutions actually make sense.

OpenStudy (studygurl14):

D? ^

OpenStudy (jhannybean):

Well, if you think it is D, then plug in values for k that satisfy both x = 0 and x = 1/2

OpenStudy (anonymous):

For example first option has \(2k+\pi/3\).

OpenStudy (freckles):

2kpi+pi/3

OpenStudy (freckles):

should be that ^

OpenStudy (anonymous):

No way \(2k\) makes any sense.

OpenStudy (studygurl14):

@Jhannybean I plugged in 1 for k + pi/3, and it worked. I got 0

OpenStudy (jhannybean):

:)

OpenStudy (freckles):

a lot of the thingys are missing pi

OpenStudy (studygurl14):

Thanks @Jhannybean

OpenStudy (jhannybean):

Keep going @StudyGurl14

OpenStudy (jhannybean):

Wait a minute, do you understand, @freckles ?

OpenStudy (jhannybean):

If not, explain @StudyGurl14 :)

OpenStudy (freckles):

Yes I been saying done of these choices are correct... lol. but one of them is kinda close.

OpenStudy (freckles):

none*

OpenStudy (studygurl14):

Wait @Jhannybean It can't be D...cause I plugged in 2 for k, and it didn't work. it didn't result in 0

OpenStudy (studygurl14):

wait, hold on i made a mistake

OpenStudy (jhannybean):

But you have two conditions to satisfy, do you not?

OpenStudy (studygurl14):

It's not D, I don't think...

OpenStudy (studygurl14):

I'm back to thinking it is B, but even that doesn't work right...*sigh*

OpenStudy (freckles):

this is what I'm saying... the choices should look like this: \[A) 0+\pi k , 2k \pi+\frac{\pi}{3}, 2k \pi-\frac{\pi}{3} \\ B)0+\pi k, \frac{\pi k}{3}, \frac{2 \pi k}{3} \\ C) 0+ \pi k, 2k \pi+\frac{\pi}{3}, k \pi+\frac{2\pi}{3} \\ D) 0+\pi k , k \pi +\frac{\pi}{3}, k \pi +\frac{2\pi}{3}\]

OpenStudy (studygurl14):

I don't think so @freckles ...

OpenStudy (studygurl14):

Why would they need two pi's?

OpenStudy (mertsj):

If tan x = 0 then x is 0 or pi \[0^{o}+\pi k\]

OpenStudy (mertsj):

If sec x = 2 then cos x = 1/2 and x = pi/3 or 5pi/3

OpenStudy (freckles):

pi/3+2pi*k this explains all the angles that end up at that one particular coordinate (1/2, sqrt(3)/2) this tells us that the following are solutions pi/3 pi/3+2pi pi/3+4pi and so on... if we go pi/3 and then 2pi/3 we land at the same location we stopped at before

OpenStudy (mertsj):

x=pi/3 \[\frac{\pi}{3} +2k \pi \]

OpenStudy (freckles):

pi/3+2 makes no sense at all

OpenStudy (studygurl14):

Okay, so I used mathway, and it says this:

OpenStudy (mertsj):

5pi/3 is the same as - pi/3

OpenStudy (studygurl14):

BUT, that's not an answer choice....*sigh*

OpenStudy (freckles):

oops /3 was a type-o

OpenStudy (mertsj):

So choose the first answer and be done with it already

OpenStudy (freckles):

cos(x)=cos(-x) so if pi/3 is a solution then -pi/3 is also a solution

OpenStudy (freckles):

but i would still say none of these and put the write solution :p

OpenStudy (freckles):

right

OpenStudy (jhannybean):

That's what @Mertsj is saying,

OpenStudy (studygurl14):

OH! So then A

OpenStudy (freckles):

but it really isn't A

OpenStudy (freckles):

but A is the closest

OpenStudy (studygurl14):

I see. Thanks.

OpenStudy (freckles):

\[2\pi n+\frac{\pi}{3} , 2 \pi n+\frac{-\pi}{3}\]

OpenStudy (studygurl14):

It was A...man if that was the practice test, I'm afraid of the real thing...haha

OpenStudy (freckles):

hopefully there won't be any type-os :p

OpenStudy (studygurl14):

yeah...stupid Connections Academy...

OpenStudy (anonymous):

If it was a real test, then you'd have to tell a teacher that the answers are wrong.

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!