Question

What is the
Sin (-25 pi/6) and
Cos (-25 pi/3)
Thanks

Answer 1

\[\sin (\frac{ -25\pi }{ 6 } ) = -\sin (\frac{ 25\pi }{ 6 } ) \]

=\[-\sin (\frac{ 25\pi }{ 6 } ) = \sin( 4\pi\frac{ \pi }{ 6 })\]

since 4pi = 2*2pi and it's multiplier of 2pi we just have to ignore that
so....\[- \sin( 4\pi\frac{ \pi }{ 6 }) = \sin \frac{ \pi }{ 6 } \]

Answer 2

did ya get it.... or should I explain y I ignore 4pi out of the expression ?

Answer 3

can u work out Cos (-25 pi/3) ?

Answer 4

so its gonna be -1/2 not 1/2 right? for the first one

Answer 5

OH GOD....am so sorry. I have frgt to put the negative sign ..... so it's should be -1/2

Answer 6

But the theory for the second one is different....
though
\[\sin (-\theta) = - \sin \theta \]
the cos value is different...
for cos value it should be...
\[\cos (- \theta) =\cos \theta\]
*NOTHING CHANGES for cos value

Answer 7

can ya follow the same steps as for the sin value here... ? but remember wt I said earlier...
just tell if ya want any more help!

Hope this will help ya...!

Answer 8

thank you so much
got it

Answer 9

U r welcome!