sin(a+π/3)+sina=-4√3/5,-π/2

来源：学生作业帮助网 编辑：作业帮 时间：2024/11/16 22:24:46

sin(a+π/3)+sina=-4√3/5,-π/2
sin(a+π/3)+sina=-4√3/5,-π/2

sin(a+π/3)+sina=-4√3/5,-π/2
∵－π/2＜a＜0,∴π/6－π/2＜a＋π/6＜π/6,∴－π/3＜a＋π/6＜π/6.
∵sin（a＋π/3）＋sina＝－4√3/5,∴2sin（a＋π/6）cos（π/6）＝－4√3/5,
∴sin（a＋π/6）＝－4/5,结合－π/3＜a＋π/6＜π/6,得：
cos（a＋π/6）＝√（1－16/25）＝3/5.
∴cosa＝cos［（a＋π/6）－π/6］＝cos（a＋π/6）cos（π/6）＋sin（a＋π/6）sin（π/6）
＝（3/5）×（√3/2）＋（－4/5）×（1/2）＝3√3/10－4/10＝（3√3－4）/10.

√3cosa / 2 + 3sina/ 2 = -4√3/5
√3sin(a+β）= -4√3/5 ，tanβ = √3/3
sin（a + π/6） = -4/5
√3sina /2 + cosa /2 = -4/5
100cos²a + 80cosa -11= 0
cosa =

sinA=3sin(2π/3-A) SINA=?sinA=3sin(2π/3-A) SINA=?答案是-3√3cosA 已知sin(a+π/3)+sina=-4√3/5,-π/2 sin(a+π/3)+sina=-4√3/5,-π/2 已知sin(a+π/3)+sina=-4√3/5,-π/2 1- sin(2π/3 - a)/sina sin(a+kπ)=2cos[a+(k+1)π].求5cosa+3sina/4sina-2cosa sin(a+kπ)=2cos[a+(k+1)π].求5cosa+3sina/4sina-2cosa 为啥sina+cosa=√2sin(a+π/4) sin(6/π-a)=1/3 sina= 已知sin(π+a)=1/3,则sina= sin(3π-a)=sina?三角函数诱导 sin(a-pia/4)=3/5,求sina 已知tan{π/4+a}=3,求sina*sin(3π /2 +a)-sin^2a+1的值 设(sina)^2-sina-2(cosa)^2=0,求sin(a-3π/2) 若sina+f(a)=2/3,f(a)=sin(a+π/2),求(√2sin(2a-π/4)+1)/(1+tana)的值 sin(a-兀/4)=√2/3,求sina已知sin(a-兀/4)=√2/3求sina 证明sinA+sin(A+2π/3)+sin(A-2π/3)=0 证明sinA+sin(A+2π/3)+sin(A-2π/3)=0