1+cosA-2(sinA)^2=0怎么求A的度数?

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1+cosA-2(sinA)^2=0怎么求A的度数?1+cosA-2(sinA)^2=0怎么求A的度数?1+cosA-2(sinA)^2=0怎么求A的度数?原式=1+cosA-2(1-cosA)=2c

1+cosA-2(sinA)^2=0怎么求A的度数?
1+cosA-2(sinA)^2=0怎么求A的度数?

1+cosA-2(sinA)^2=0怎么求A的度数?
原式=1+cosA-2(1-cosA)=2cosA+cosA-1=(cosA+1)(2cosA-1)=0 A=2Kπ+1/2π或2Kπ±π/3