Question

if sin ( A + B +C ) = 1 , Cos ( B + C ) = 1/2 and sin b = root3/2 find the value of A , B and C

Answer 1

hi!
sin(A+B+C)=1
sin90°=1
therefore A+B+C=90° ------(1)
cos(B+C)=1/2
cos60°=1/2
therefore, B+C=60°------(2)

sinB=√3/2
sin60°=√3/2
therefore, B=60°
substituting this in equation (2)
we get ,
C=60°-60=0°
substituting value of B+C =60° in (1)
A+60°=90°
A=90°-60°=30°