1 Find the exact value of the cosine and sine of the given a
1) Find the exact value of the cosine and sine of the given angle = -43pi/6
2) If sin()=25/5 and pi/2 < < pi, what is cos()?
3) =3 is found in what quadrant and what does ¯ equal to?
Please show the work.
Solution
1) = -43pi/6
cos( -43pi/6 ) = cos(43pi/6)
= cos(6pi +7pi/6) = cos(7pi/6)
= cos( pi+pi/6) = -cospi/6
= -sqrt3/2
sin((-43pi/6) = -sin(6pi + 7pi/6)
= -sin(7pi/6)
= -sin(pi + pi/6) = sinpi/6
= 1/2
2) sin()=25/5 and pi/2 < < pi, what is cos()
cos() = sqrt( 1 - sin^2)
= -sqrt( 1- (2sqrt5/5)^2 ) ( cos is -ve in QII as given pi/2 < < pi)
= sqrt( (25 - 20)/25)
= sqrt(5/25) = 1/sqrt5
3) =3 is found in what quadrant and what does ¯ equal to
I understand ¯ = -3 deg.So, it lies in IVrt quadrant and can written as :
¯ = 360 - = 277 deg
