在三角形ABC中,已知2B=A+C,b^2=ac,则B-A=?A.0 B.Π/6 C.Π/4
在三角形ABC中,已知2B=A+C,b^2=ac,则B-A=?
A.0 B.Π/6 C.Π/4 D.Π/3
人气：231 ℃ 时间：2020-09-05 09:59:59
解答
A + B + C = 180,2B = A + C => B = 60
b^2 = a^2 + c^2 - 2ac * cosB = a^2 + c^2 - ac = ac => (a - c)^2 = 0 => a = c => A = C = 60
B - A = 0
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