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Mathematics 7 Online
OpenStudy (anonymous):

Help with precal please!

OpenStudy (anonymous):

okay?

OpenStudy (anonymous):

\[2\cos ^{2}x = 1\]

OpenStudy (anonymous):

yes it's solving trigonometric equations

OpenStudy (anonymous):

solve for cosx

OpenStudy (anonymous):

\[\left(\begin{matrix}2Cos ^{2}x \\ 2\end{matrix}\right) = \frac{ 1 }{ 2 }\]

OpenStudy (anonymous):

\[Cos^2x = \frac{ 1 }{ 2 }\]

OpenStudy (anonymous):

\[x = \cos^{-1} (\frac{ 1 }{ 2 })\]

OpenStudy (anonymous):

Then using a calculator or something do the right side of the last step

OpenStudy (anonymous):

you're just supposed to simplyfy it down to cosx = whatever and then you go to the unit circle and use that to determine where that value occurs for cos and that's your answer

OpenStudy (anonymous):

oh shot I missed cos^2, ignore the last step

OpenStudy (anonymous):

Oh I see so in the end you have \[Cosx = \sqrt{\frac{ 1 }{ 2 }}\]

OpenStudy (anonymous):

I got it down to cos ^2x = 1/2 but from there you would have to square both sides and square root of 1/2 isn't on the unit circle

OpenStudy (anonymous):

Any ideas?

OpenStudy (anonymous):

I'm looking through my notes, I just did this unit

OpenStudy (anonymous):

I'm pretty sure it's 60 degrees but I want to make sure

OpenStudy (anonymous):

Ok

OpenStudy (anonymous):

Actually I don't know.... I could try messaging someone to help you out.

OpenStudy (anonymous):

That would be great. 60 degrees is 1/2 but i need square root of 1/2 which isn't an option so I messed up somewhere

OpenStudy (anonymous):

yeah

OpenStudy (anonymous):

@TheSmartOne

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