sin(a-兀/4)=√2/3,求sina已知sin(a-兀/4)=√2/3求sina

sin（-19π/6）=?已知[3Sin(π+a)+Cos(π-a)]/4Sin(-a)-Sin(5π/2+a)=2，求tan a tan a =3求4sin a-2cos a/5cos+3sin a sin阝=1/3,sin(a+阝)=1,求sin(2a+3阝) 已知3SIN^2A+2SIN^2B=5SINA,求SIN^2A+SIN^2B范围 已知sin(a)=2sin(b)求sin(a/2)/sin(b/2)的值. 已知a(-0,兀且2SIN A-SIN ACOS A-3COS A=0求SIN(+兀/4)/SIN 2A+COS 2A+1的值 1-sin a+sin a的平方-sin a的立方+……若a是正锐角,且sin a-cos a=0.5,求1-sin a+sin^2a-sin^3a+…… 已知sin[a-b]cos a-cos[b-a]sin a=3/5,b是第三象限角,求sin[b+5π/4]的值第一题1/2cos x-√3/2sin x第二题√3sin x+cos x第三题√2[sin x-cos x]第四题√2cos x-√6sin x sin(a-兀/4)=√2/3,求sina已知sin(a-兀/4)=√2/3求sina 若sin(a-兀)=2cos(2兀-a)求sin(兀-a)+5cos(2兀-a)/3cos(兀-a)-sin(-a)的值 已知(4sin a－2cos a)／(5cos a +3sin a)=6/11,求cos＾4 a－sin＾4 a 已知sina-2cosa=0,求 [sin(兀-a)cos(2兀-a)sin(-a+3兀/2)]/tan(-a-兀)sin(-兀-a)的值. 已知sin a-2cos a=0 求4sin^2 a-3sin a x cos a-5cos^2 a的值 已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4)4sin a已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4) (4sin a-2cos a)/(5cos a+3sin a) a为任意角 已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4)4sin a已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4) (4sin a-2cos a)/(5cos a+3sin a) a为任意角 已知tan a=-1/3,求4sin a-2cos a/5cos a+3sin a= 已知tan a=2,求:(4*sin a-2*cos a)/(5*sin a+3*cos a)的值 已知sin(3π+a)=2sin[(3π/2)+a],求sin^2a+sin2a的值