In triangle ABC write cos(B+C/2) in terms of angle A. ANSWER...
Answers
Answered by
36
we know A+B+C=180
B+C=180-A
so
cos(B+C/2)=cos(180-(A)/2)=sinA/2...
B+C=180-A
so
cos(B+C/2)=cos(180-(A)/2)=sinA/2...
Answered by
31
Since, A + B +C = 180°
Therefore, B+C = 180°-A
Put Value of B+C in equation 1
We get, Cos(180°-A)/2
Next............
Sin[90°-(180°-A)/2]
Sin(180°-180°+A)/2
Sin(A/2)
Therefore, B+C = 180°-A
Put Value of B+C in equation 1
We get, Cos(180°-A)/2
Next............
Sin[90°-(180°-A)/2]
Sin(180°-180°+A)/2
Sin(A/2)
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