Calculate sinb if cosb=-1/2 and b is in the third quadrant .
Solution
First, we have to emphasize that if b is in the third quadrant, the value of sin b is negative.
Due to the fact that the value of cosb is given, from enunciation, we\'ll calculate the value of sin
b, with the help of fundamental formula of trigonometry:
(sin b)^2 + (cos b)^2 = 1
But cos b = -1/2
(sin b)^2 + (-1/2)^2 = 1
We\'ll subtract (-1/2)^2 both sides:
(sin b)^2 = 1 -1/4
sin b = -sqrt (3/9)
sin b = -(sqrt 3)/3.
Calculate sinb if cosb=-12 and b is in the third quadrant .Solu.pdf
1. Calculate sinb if cosb=-1/2 and b is in the third quadrant .
Solution
First, we have to emphasize that if b is in the third quadrant, the value of sin b is negative.
Due to the fact that the value of cosb is given, from enunciation, we'll calculate the value of sin
b, with the help of fundamental formula of trigonometry:
(sin b)^2 + (cos b)^2 = 1
But cos b = -1/2
(sin b)^2 + (-1/2)^2 = 1
We'll subtract (-1/2)^2 both sides:
(sin b)^2 = 1 -1/4
sin b = -sqrt (3/9)
sin b = -(sqrt 3)/3
