cos²;(-a)-sin(-a)/ tan(2π+a)化簡
cos²;(-a)-sin(-a)/ tan(2π+a)
=cos²;a+sina/tana
=cos²;a+cosa
=(cosa+1/2)²;-1/4
已知tanα=2,求sinacosa
sina/cosa=2
sin^2+cos^2=1
求出sin,cos
已知tan(a+π/4)=2,則1+sinacosa-2(cosa)^2
tan(a+π/4)=2tan(a+π/4-π/4)= [tan(a+π/4)-tan(π/4)]/[1+tan(a+π/4)tan(π/4)]=(2-1)/3=1/3所以sina/cosa=1/3cosa=3sinacos²;a+sin²;a=110sin²;a=1 sin²;a=1/10,cos²;a=9/10sina co…
已知sinacosa=-1/4求tan平方a+1/tan平方a=
1/sinacosa=-4
(sin²;a+cos²;a)/sinacosa=-4
所以sina/cosda+cosa/sina=-4
tana+1/tana=-4
兩邊平方
tan²;a+2+1/tan²;a=16
所以原式=14
(1+cos方a)*tan方a -sec方a的最簡形式?
(1+cos²;a)*tan²;a -sec²;a=(1+cos²;a)*(sin²;a/cos²;a)-(1/cos²;a)=(sin²;a+sin²;a *cos²;a-1)/cos²;a=(-cos²;a+sin²;a *cos²;a)/cos²;a=-1+sin …
(1+cos平方)tan平方-SEC平方最簡形式
(1+cosx^2)tanx^2 - secx^2 =(1+cosx^2)*(sinx^2/cosx^2)-(1/cosx^2)=sinx^2/cosx^2 + sinx^2 -(1/cosx^2)=(sinx^2-1)/cosx^2 + sinx^2 =-cosx^2 /cosx^2 + sinx^2 =sinx^2 - 1=-cosx^2
(1+cos^2a)tan^2a-sec^2a的最簡形式
(1+cos^2a)tan^2a-sec^2a=(1+cos²;a)*sin²;a/cos²;a-1/cos²;a=(sin²;a+sin²;acos²;a-1)/cos²;a=(sin²;a+sin²;acos²;a-sin²;a-cos²;a)/cos²;a=cos²;a(s…
如果sec(A)+ tan(A)= 2,請求出cos(A)
secA+tanA=(1+sinA)/cosA=2
sinA=2cosA-1
(cosA)^2+(sinA)^2=1
5(cosA)^2-4cosA+1=1
cosA=4/5
cot(-π-θ)等於什麼?等於-cot(π+θ)嗎
cot(-π-θ)=-cot(π+θ)=-cotθ
設tanα=1/2,tanβ=1/3,則cot(α+2β)的值
tan(A+B)=(tanA+tanB)/(1-tanAtanB)
所以tan2β=3/4
tan(α+2β)=2,
cot(α+2β)=1/tan(α+2β)=1/2