已知sin^2 A+sin^2 B+1/4=sinAsinB+1/2(sinA+sinB),求锐角A,B的值.
来源:学生作业帮 编辑:搜搜考试网作业帮 分类:数学作业 时间:2024/06/23 17:58:30
已知sin^2 A+sin^2 B+1/4=sinAsinB+1/2(sinA+sinB),求锐角A,B的值.
sin^2 A+sin^2 B+1/4=sinAsinB+1/2(sinA+sinB),
4sin^2 A+4sin^2 B+1-4sinAsinB-2sinA-2sinB=0
4[sin^2A-2sinAsinB+sin^2 B]+[4sinAsinB-2sinA-2sinB+1]=0
4[sinA-sinB]^2+(2sinA-1)(2sinB-1)=0
sinA-sinB=0
(2sinA-1)(2sinB-1)=0
sinA=1/2
sinB=1/2
A=B=30°
4sin^2 A+4sin^2 B+1-4sinAsinB-2sinA-2sinB=0
4[sin^2A-2sinAsinB+sin^2 B]+[4sinAsinB-2sinA-2sinB+1]=0
4[sinA-sinB]^2+(2sinA-1)(2sinB-1)=0
sinA-sinB=0
(2sinA-1)(2sinB-1)=0
sinA=1/2
sinB=1/2
A=B=30°
已知sinA=3/5 sinB=1/2 A、B均为锐角 求sin(2A+2B)的值
a,b为锐角,3sina+3sinb=1 ,3sin(2a)-2sin(2b)=0 求sin(a+2b)
已知sina+sinb=1/3,sinb-cosa=1/2,求sin(a-b)的值
已知sina+cosb=1/2,cosa+sinb=3/4,求sin(a+b)
sina+cosb=1/2,cosa+sinb=1/3 求sin(a+b)的值
在三角形ABC中,已知(b+a)/a=sinB/(sinB-sinA).且2sinAsinB=2sin^2C,试判断该三
函数:已知sina+cosB=1/2,cosa+sinB=1/3,求sin(a+B)的值
已知cos(a+B)+1=0,求证sin(2a+B)+sinB=0?(提示:sin(-a)=-sina).
已知 sina+sinb=1/4 ,cosa+cosb=1/3 求sin(a+b) ,cos(a+b)的值
已知cosa-cosb=1/2,sina-sinb=-1/3,求cos(a-b),sin(a+b)
已知sina+sinB=-2/3,cosa-cosB=1/3.求cos(a+B),sin(a+B)
已知sina+sinb=根号2,求sinacosb及sin^4a+cos^4b的值