sinB+cosB=√2
(√2)sin[B+(π/4)]=√2
B+(π/4)=π/2
B=π/4
sinB=1/√2
根据正弦定理
a/sinA=b/sinB
sinA=asinB/b=1/2
A=π/6或A=5π/6(舍)(√2)sin[B+(π/4)]=√2这步怎么来的Asinx+BcosB=[√(A²+B²)]sin(x+φ) tanφ=B/A