4woods中国官网:证明sin3a=3sina-4sin立方a

来源：百度文库 编辑：中科新闻网 时间：2024/05/17 01:03:40
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sin3a=sin2a*cosa+cos2a*sina
=2sina*(cosa)^2+sina*(1-2(sina)^2)
=2sina-2(sina)^3+sina-2(sina)^3
=3sina-4(sina)^3

sin3a
=sin(2a+a)
=sin2a*cosa+cos2a*sina
=2sina*(cosa)^2+sina*[1-2(sina)^2]
=2sina-2(sina)^3+sina-2(sina)^3
=3sina-4(sina)^3

证明sin3a=3sina-4sin立方a 证明sin3a=3sina-4sin立方a 证明sin3a=3sina-4sin立方a sinA+sin5A+sin9A=sin3A+sin7A 已知：sinA+sin^2A=1 求sin^2+sin^4的值 sina+cosa/sina-cosa = 2 则sin(a-5pai)sin(3pai/2 - a)=?? sin^3A+cos^3A=1,分别求sinA+cosA和sin^4A+cos^4A的值. 若sinA的立方+cosA的立方=1，求sinA+cosA=? 已知3sin^A+2sin^B=2sinA 求cos^A+cos^B的最值 (sin三次方A+2cosA)/(sinA-3cos三次方A）=？