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Mathematics 15 Online
OpenStudy (jojokiw3):

How do I do this trig question?

OpenStudy (jojokiw3):

\[\cos (\frac{ -13\pi }{ 6 }) + \sin \frac{ 13\pi }{ 6 }\]

OpenStudy (jdoe0001):

hmmm I'd guess you simply get their values and add them up :)

OpenStudy (jdoe0001):

since it's not really an equation anyway

OpenStudy (xapproachesinfinity):

you can use \[13\pi/6=2\pi +\pi/6\] use then the fact that sin and cos are 2pi periodic

OpenStudy (xapproachesinfinity):

yah i guess too

OpenStudy (jojokiw3):

\[\frac{ \sqrt{3} + 1 }{ 2 }?\]

OpenStudy (xapproachesinfinity):

you have cos(-x)=cos(x) so you just get rid of - sign for cos (-13pi/6)

OpenStudy (xapproachesinfinity):

hmm not quite

OpenStudy (xapproachesinfinity):

what is sin pi/6

OpenStudy (xapproachesinfinity):

and cos pi/6

OpenStudy (jdoe0001):

\(\bf cos \left( -\cfrac{ 13\pi }{ 6 } \right) + sin \left( \cfrac{ 13\pi }{ 6 } \right) \\ \quad \\ cos(-\theta)=cos(\theta)\qquad thus \\ \quad \\ cos \left( -\cfrac{ 13\pi }{ 6 } \right) + sin \left( \cfrac{ 13\pi }{ 6 } \right)\iff cos \left( \cfrac{ 13\pi }{ 6 } \right) + sin \left( \cfrac{ 13\pi }{ 6 } \right)\)

OpenStudy (xapproachesinfinity):

eh hold on i guess you are correct my bad

OpenStudy (jojokiw3):

Haha lol. I was panicking for a moment there.

OpenStudy (xapproachesinfinity):

root 3+1 /2 is good

OpenStudy (jojokiw3):

Thanks guys. :) I appreciate the help.

OpenStudy (jdoe0001):

yw

OpenStudy (xapproachesinfinity):

yw

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