sinA+sinB=1/4,cosA+cosB=1/3,求cos(A-B)的值和sin(A+B)的值
来源:学生作业帮 编辑:大师作文网作业帮 分类:数学作业 时间:2024/09/20 20:33:46
sinA+sinB=1/4,cosA+cosB=1/3,求cos(A-B)的值和sin(A+B)的值
cos(A-B)=cosAcosB+sinAsinB
(sinA+sinB)^2+(cosA+cosB)^2=sin^2A+2sinAsinB+sin^2B+cos^2A+2cosAcosB+cos^B=2+2cos(A-B)=1/9+1/16
cos(A-B)=-263/288
(sinA+sinB)(cosA+cosB)=sinAcosA+sinBcosB+sinAcosB+cosAsinB=cos(A-B)+sin(A+B)=1/12
sin(A+B)=287/288
(sinA+sinB)^2+(cosA+cosB)^2=sin^2A+2sinAsinB+sin^2B+cos^2A+2cosAcosB+cos^B=2+2cos(A-B)=1/9+1/16
cos(A-B)=-263/288
(sinA+sinB)(cosA+cosB)=sinAcosA+sinBcosB+sinAcosB+cosAsinB=cos(A-B)+sin(A+B)=1/12
sin(A+B)=287/288
已知 sina+sinb=1/4 ,cosa+cosb=1/3 求sin(a+b) ,cos(a+b)的值
已知cos(a-b)=3/1,求(sina+sinb)(sina+sinb)+(cosa+cosb)(cosa+cosb
sina+cosb=1/2,cosa+sinb=1/3 求sin(a+b)的值
已知sina+sinb=1,cosa+cosb=0求cos(a+b)的值
函数:已知sina+cosB=1/2,cosa+sinB=1/3,求cos(a-B)的值
已知sina-sinb=-1/3,cosa-cosb=1/2,求cos(a-b)的值
已知sina+sinb=1/2,cosa+cosb=1/3,求cos(2a-b/2)的值
①已知sina-sinB=-1/3,cosa-cosB=1/2,求cos(a-B)的值.
已知cosa+cosb=1/2,sina+sinb=1/3,求cos(a-b)的值?
已知sina-sinb=-1/3 cosa-cosb=1/2求的cos(a-b)值
若sinA+sinB=1/2,cosA+cosB=2分之根号3,求cos(A+B)的值
已知sinA+sinB=1/3,cosA+cosB=2/5,求cos(A-B)的值.