pre cal
posted by ali on .
assume the angle is in the first quadrant, and sin theta equals 1/5. what is sin 2 theta?

sin(theta)=1/5
cos(theta)=sqroot[1sin(teta)^2]
cos(theta)=sqroot[1(1/5)^2]
cos(theta)=sqroot(11/25)
cos(theta)=sqroot(25/251/25)
cos(theta)=sqroot(24/25)
cos(theta)=sqroot(6*4/25)
cos(theta)=sqroot(6*2^2/5^2)
cos(theta)=(2/5)*sqroot(6)
sin(2theta)=2*sin(theta)*cos(theta)
sin(2theta)=2*(1/5)*(2/5)sqroot(6)
sin(2theta)=(4/25)*sqroot(6)