1-2sin²θ*cos²θ怎么化成1-1/2sin²2θ
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/01 03:43:49
![1-2sin²θ*cos²θ怎么化成1-1/2sin²2θ](/uploads/image/z/1100392-16-2.jpg?t=1-2sin%26%23178%3B%CE%B8%2Acos%26%23178%3B%CE%B8%E6%80%8E%E4%B9%88%E5%8C%96%E6%88%901-1%2F2sin%26%23178%3B2%CE%B8)
1-2sin²θ*cos²θ怎么化成1-1/2sin²2θ
1-2sin²θ*cos²θ怎么化成1-1/2sin²2θ
1-2sin²θ*cos²θ怎么化成1-1/2sin²2θ
∵sin2θ=2sinθcosθ;
∴1-2sin²θcos²θ=1-(2sinθcosθ)²/2=1-sin²(2θ)/2;
如果本题有什么不明白可以追问,
1-2sin²θcos²θ=1-(2sinθcosθ)²/2
=1-sin²2θ/2.