Express sin(-113 degree) as the function of a positive acute angle less than 45 degree
on which quadrant do you think the angle \(-113^o\) is at?
3rd quadrant
ok, if you were to go counterclockwise, or 'positive' movement, where would the \(113^o\) would be at? II quadrant, well, what you're after is its SUPPLEMENTARY angle
67 degree ???
yes, \(67^o\) on the II quadrant, where SINE is positive
and 67 is also acute
but the answers are 1) sin 57 2) cos 23 3) -cos 23 4) csc 23
ohh, it has to be less than 45, ok
that's why i'm confusing :D
do you have any idea?
no yet :|
i typed in my calculator and i found that -cos23 is equal to sin(-113)
right, it has to be it's counterpart in the internal angles, cos(23)
the sin(60) = cos(30), becuase THE SAME line makes 60degrees from the origin, AND 30degrees from the arc, and those internal angles are usually a cos/sin relation
|dw:1367708552997:dw|it looks like this right ?
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