p=cos^2α+cos^2(60度-α)+cos^2(60度+α)的值?
来源:学生作业帮 编辑:搜狗做题网作业帮 分类:数学作业 时间:2024/08/09 14:35:38
p=cos^2α+cos^2(60度-α)+cos^2(60度+α)的值?
![p=cos^2α+cos^2(60度-α)+cos^2(60度+α)的值?](/uploads/image/z/19985067-27-7.jpg?t=p%3Dcos%5E2%CE%B1%2Bcos%5E2%2860%E5%BA%A6-%CE%B1%29%2Bcos%5E2%2860%E5%BA%A6%2B%CE%B1%29%E7%9A%84%E5%80%BC%3F)
p=cos²a+(cosacos60+sin60sina)²+(cosacos60-sin60sina)²
=cos²a+cos²acos²60+2cosacos60sin60sina+sin²60sin²a+cos²acos²60-2cosacos60sin60sina+sin²60sin²a
=cos²a+2cos²acos²60+2sin²60sin²a
=cos²a+2cos²a*1/4+2*3/4sin²a
=cos²a+2cos²a*1/4+2*3/4sin²a
=3/2*cos²a+3/2*sin²a
=3/2*(cos²a+sin²a)
=3/2
=cos²a+cos²acos²60+2cosacos60sin60sina+sin²60sin²a+cos²acos²60-2cosacos60sin60sina+sin²60sin²a
=cos²a+2cos²acos²60+2sin²60sin²a
=cos²a+2cos²a*1/4+2*3/4sin²a
=cos²a+2cos²a*1/4+2*3/4sin²a
=3/2*cos²a+3/2*sin²a
=3/2*(cos²a+sin²a)
=3/2
已知5(cosα)^2+4(cosβ)^2=4cosα,则(cosα)^2+(cosβ)^2的取值范围是?
求和:cos(0)+cos(α)+cos(2α)+cos(3α)+……cos(nα)
已知sinα+3cosα=2,求(sinα-cosα)/(sinα+cosα)的值
已知sinα-2cosα=0 (1)求cos^2α-sinαcosα的值
已知1+cosα/cosα=-1/2求cosα/sinα-1
若sinα+cosα=根号2,则sinα-cosα的值等于?
化简三角函数[sin(α+pi)*cos(pi+α)*cos(α+2pi)]/[tan(pi+α)*cos^3(-α-p
若cos(α-3π/2)=1/5,求-cosα的值.
一道三角函数的化简题化简cosα.cos(α/2).cos(α/2^2).cos(α/2^3)……cos(α/2^(n-
cos(α-β)cos(α+β)=1/2,求sinβ的平方+cosα的平方
三角函数题2sin^2α-cos^α+sinα*cosα-6sinα+3cosα=0 求(2cos^α+2sinαcos
已知3sinα-2cosα=0,求(cosα-sinα)/(cosα+sinα)+(cosα+sinα)/(cosα-s