sin(a-π/4)
=sinacosπ/4-cosasinπ/4
=sina*√2/2-cosa*√2/2
=√2/2)sina-cosa)
sin(a-π/4)怎么推算出 根号2/2(sina-cosa)?
2个回答
相关问题
-
若a∈（π/2,π）且sina=4/5,则sin(a-π/4)-（根号2）/2 cosa=?
-
cos2a/sin(a-π/4) =-根号（2）/2,则cosa+sina的值为?
-
sin(π/2+a)=cosa,cos(π/2+a)=-sina,sin(π/2-a)=cosa,cos(π/2-a)=
-
sin(a+kπ)=2cos[a+(k+1)π].求5cosa+3sina/4sina-2cosa
-
若sin2a=-(2根号2)/3 ,cosa＞0 ,a∈（0,7π/4）,则sina=
-
若cos2a/sin(a-π/4)=-根号2/2 则sina+cosa 的值为多少?
-
(sina/2+cosa/2)^2+2sin^2(π/4-a/2)
-
已知sin(π-a)-cos(π+a)=√2/3 (π/2〈a〈π) 求⑴sina-cosa ⑵sina*cosa⑶si
-
已知a为第二象限角,且sina=根号15/4,求sin(π-a)/((sin(a+π/2)+cosa+1)
-
已知sin(a/2)=4/5,a∈(π,2π),求sina,cosa,tana