In △ ABC, ∠ C = 90 ° if side length a = M & # 178; - N & # 178;, C = M & # 178; + n & # 178; (M > n > 0), then B=

In △ ABC, ∠ C = 90 ° if side length a = M & # 178; - N & # 178;, C = M & # 178; + n & # 178; (M > n > 0), then B=

c²=a²+b²(m²+n²)²=(m²-n²)²+b²b²=(m²+n²)²-(m²-n²)²=(m²+n²+m²-n²)(m²+n²-m²+n²)...