Sina+sin^2a=1,cos^2a+cos^s4a+cos^6a

来源：学生作业帮助网编辑：作业帮时间：2024/04/28 02:46:52

Sina+sin^2a=1,cos^2a+cos^s4a+cos^6a
Sina+sin^2a=1,cos^2a+cos^s4a+cos^6a

Sina+sin^2a=1,cos^2a+cos^s4a+cos^6a
化简有sinθ=cos^2θ
同时乘以sinθ
sin^2θ+sin^3θ=sinθ
∴sin^3θ=sinθ-sin^2θ=cos^2θ-sin^2θ=cos2θ
∴=sinθ+sin^2θ+sin^3θ
=1+sin^3θ
=1+cos2θ
=2cos^2θ
=2sinθ
又sin²θ+sinθ-1=0 解出

设sina=t
t+t^2=1
t^2+t-1=0
delta=1+4=5
t1=-1+√5/2
t2=-1-√5/2(舍)
sina=√5-1/2
cos^2A+cos^6A
=sinA+sin^3A
=sinA+sinA(1-sinA)
=sinA+sinA-(sinA)^2
=2sinA-sin^2A
=2sinA-(1-sinA)
=3sinA-1
=3*√5-1/2-1
=3√5-5/2

sin(a/2)cos(a/2)=(1/2)sina Sina+sin^2a=1,cos^2a+cos^s4a+cos^6a 已知sin a+cos a=1/2 sina*cosa=?cos a/sina+sina/cosa=? 为什么 tan a +1/tan a=sin^2 a +cos^2 a/(sina cos a) sinA+sin^2A=1,cos^2A+cos^6A=? 若sina+sin^2a=1,求cos^2a+cos^4a的和已知sina+sin^2a=1,求3cos^2a+cos^4a-2sina+1 为什么1+sina=sin^2(a/2)+2sin(a/2)cos(a/2)+cos^2(a/2) 若sin^2+sina=1,则cos^4a+cos^2a=—— 已知sina+sin^2a=1,则cos^2a+cos^6a+cos^8a= sin(2a+β)/sina-2cos(a+β)=sinβ/sina 证明1-COS^2α/(SINα-COSα)-SINα+COSα/(TAN^2a-1)=SINa+COSa 若tan a=1/3,则sin^2 a- sina*cosa -cos^2 a= 解方程A sin^2a+cos^2a=1 B sina/cosa=tana 已知 a为第二象限,证明:2sinαcosα/(sinα+cosα-1)(sinα+cosα+1)=(1+cosα)/sina 已知tan a=2,求sina-cos分之sin a+cos a 已知3sina-2cos=o,求下式的值（1）（cosa-sina)/(cosa+sina) (2)sin^2a-2sinacosa+4cos^2a cos^2a-sin^2a=(cosa+sina)(cosa-sina)吗?求解