(sin theta)^2+(cos theta)^2=1;
(sin theta)^2+1/10=1;
(sin theta)^2=9/10
sin theta= 3/(sqrt10)
OR
sin theta=-3/(sqrt10)
But since theta is a first quadrant angle
==> sin theta is positive
Therefore, sin theta= 3/(sqrt10)
theta is a first quadrant angle in standard position and cos theta = 1/(sqrt10) .
Find the exact value of sin theta,
1 answer
2 answers