神马作文网cos8θ-sin8θ=?
来源：学生作业帮 编辑：神马作文网作业帮 分类：数学作业 时间：2024/11/12 23:49:39
cos8θ-sin8θ=?
左边=(sinθ)^8+(cosθ)^8+2(sinθcosθ)^4-2(sinθcosθ)^4
=[(sinθ)^4-(cosθ)^4]^2+2(sinθcosθ)^4
=[(sin^2θ+cos^2θ)(sin^2θ-cos^2θ)]^2+2(sinθcosθ)^4
=[(sinθ)^2-(cosθ)^2]^2+2(sinθ)^4(cosθ)^4
=(sinθ)^4+(cosθ)^4-2(sinθ)^2(cosθ)^2+2(sinθ)^4(cosθ)^4
=[(sinθ)^2+(cosθ)^2]^2-4(sinθ)^2(cosθ)^2+2(sinθ)^4(cosθ)^4
=1-4(sinθ)^2(cosθ)^2+2(sinθ)^4(cosθ)^4
=[(sinθ)^4-(cosθ)^4]^2+2(sinθcosθ)^4
=[(sin^2θ+cos^2θ)(sin^2θ-cos^2θ)]^2+2(sinθcosθ)^4
=[(sinθ)^2-(cosθ)^2]^2+2(sinθ)^4(cosθ)^4
=(sinθ)^4+(cosθ)^4-2(sinθ)^2(cosθ)^2+2(sinθ)^4(cosθ)^4
=[(sinθ)^2+(cosθ)^2]^2-4(sinθ)^2(cosθ)^2+2(sinθ)^4(cosθ)^4
=1-4(sinθ)^2(cosθ)^2+2(sinθ)^4(cosθ)^4
2根号1+sin8+根号2+2cos8=
1.sin7°+cos15°sin8°/cos7°-sin15°cos8°=
sin8*cos8判断此三角函数值得符号
关于三角函数的计算题(sin8°+sin7°cos15°)÷(cos8°-sin7°sin15°)=?
2根号下（1+sin8)-根号下（2cos8+2)
2倍更号sin8+1加根号下2cos8+2
2根号1-sin8+根号2+2cos8
化简2根号下（1+sin8)+根号下（2+2cos8)
化简 cos8次方x减sin8次方x+1/4sin2xsin4x
2(根号sin8-1)+根号下（2cos8+2）化简谢谢!
(sin7°+cos15°cos8°)/(sin7°-sin15°sin8°)的化简
化简三角函数式：根号下(2cos8+2)减去2倍根号(sin8+1)