Q1)If in a triangle, a= 6, b= 3 and cos(A-B)=4/5, then find its area?
Q2)Let the angles of a A,B,C of a triangle ABC be in A.P.and let b:c=under root(3):under root(2).Find the angle A?
Devesh Lall , 13 Years ago
Grade 11
1 Answers
Arjun Blouria
Last Activity: 13 Years ago
cos(A-B)=4/5
therefore, 1-tan2(A-B)/2 = 4/5
1+tan2(A-B)/2
By componendo dividendo,
2tan2(A-B) = 5-4
2 5+4
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