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Mathematics 16 Online
OpenStudy (anonymous):

Help ?!?!?!?!

Parth (parthkohli):

It's this right?\[\cos(2\theta) = 2\cos^2(\theta) - 1\]

Parth (parthkohli):

No, the question.

OpenStudy (anonymous):

but the first 2 and theta are not that close

Parth (parthkohli):

lol, the same thing.

OpenStudy (anonymous):

this is the picture..o lol

Parth (parthkohli):

\[\textbf{HINT}\]\(\cos(2\theta) = \cos^2(\theta) - \sin^2(\theta)\)

Parth (parthkohli):

It's just a hint. Can you now find an expression for \(\sin^2(\theta)\) in terms of \(\cos^2(\theta)\)?

OpenStudy (anonymous):

no im not really good with this

Parth (parthkohli):

Well, \(\sin^2\theta = 1 - \cos^2\theta\)

OpenStudy (anonymous):

ok

Parth (parthkohli):

Substitute \(1 - \cos^2\theta\) in \(\sin^2\theta\)

OpenStudy (anonymous):

ok

OpenStudy (raden):

i think the question ask "give an angle" to prove LHS=RHS, so we can use an angle for example the 0 degrees, pi/3, pi/4, or the others . maybe.. :)

OpenStudy (anonymous):

ok...so what should i writes as my answer...im confused

OpenStudy (raden):

u can use 0 deg, and then plug it into ur question above to prove is LHS=RHS or no

OpenStudy (anonymous):

ok

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