△ABC中,∠A,B,C所对的边为a,b,c,且满足cos2A-cos2B=2cos(π/6-A)cos(π/6+A) 1.求∠B

问题描述:

△ABC中,∠A,B,C所对的边为a,b,c,且满足cos2A-cos2B=2cos(π/6-A)cos(π/6+A) 1.求∠B