In the triangle ABC, a.b.c. are the opposite sides of a, B and C. If vector AB multiplies vector AC = vector Ba multiplies vector BC = 1 To prove a = B to find C side length, the answer should be detailed It's easy for me to understand

In the triangle ABC, a.b.c. are the opposite sides of a, B and C. If vector AB multiplies vector AC = vector Ba multiplies vector BC = 1 To prove a = B to find C side length, the answer should be detailed It's easy for me to understand

AB * accosb = Ba * bccosb, AC = BC, AC / SINB = BC / Sina, so Sina = SINB, so a = B
(2) Accosb = 1, CoSb = (a ^ 2 + C ^ 2-B ^ 2) / 2Ac, a = B. thus, C ^ 2 = 1, C = radical 2