╮(╯▽╰)╭,tanA/2=根号5,则(1-sinA-cosA)/(1-sinA+cosA)=?还有一题~sin6°c
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╮(╯▽╰)╭,
tanA/2=根号5,则(1-sinA-cosA)/(1-sinA+cosA)=?
还有一题~
sin6°cos24°sin78°cos48°的值为?
tanA/2=根号5,则(1-sinA-cosA)/(1-sinA+cosA)=?
还有一题~
sin6°cos24°sin78°cos48°的值为?
sinA=2sin(A/2)cos(A/2);1-cosA=2sin ² (A/2);1+cosA=2 cos ² (A/2)
又:tan(A/2)=√5,故:sin(A/2)cos(A/2)≠0
故:(1-sinA-cosA)/(1-sinA+cosA)
=[2sin ² (A/2)- 2sin(A/2)cos(A/2)]/[ 2 cos ² (A/2) - 2sin(A/2)cos(A/2)][分子、分母同时除以cos ² (A/2)]
=[2 tan²(A/2)- 2 tan(A/2)]/[ 2 - 2 tan(A/2)]
=(10- 2 √5)/(2 - 2 √5)
=-√5
sin6°cos24°sin78°cos48°
= sin6°sin78°cos24°cos48°
= sin6°cos12°cos24°cos48°
=16 sin6°cos6°cos12°cos24°cos48°/(16cos6°)
=8sin12° cos12°cos24°cos48°/(16cos6°)
=4sin24°cos24°cos48°/(16cos6°)
=2sin48°cos48°/(16cos6°)
=sin96°/(16cos6°)
= cos6°/(16cos6°)
=1/16
又:tan(A/2)=√5,故:sin(A/2)cos(A/2)≠0
故:(1-sinA-cosA)/(1-sinA+cosA)
=[2sin ² (A/2)- 2sin(A/2)cos(A/2)]/[ 2 cos ² (A/2) - 2sin(A/2)cos(A/2)][分子、分母同时除以cos ² (A/2)]
=[2 tan²(A/2)- 2 tan(A/2)]/[ 2 - 2 tan(A/2)]
=(10- 2 √5)/(2 - 2 √5)
=-√5
sin6°cos24°sin78°cos48°
= sin6°sin78°cos24°cos48°
= sin6°cos12°cos24°cos48°
=16 sin6°cos6°cos12°cos24°cos48°/(16cos6°)
=8sin12° cos12°cos24°cos48°/(16cos6°)
=4sin24°cos24°cos48°/(16cos6°)
=2sin48°cos48°/(16cos6°)
=sin96°/(16cos6°)
= cos6°/(16cos6°)
=1/16
╮(╯▽╰)╭,tanA/2=根号5,则(1-sinA-cosA)/(1-sinA+cosA)=?还有一题~sin6°c
(cosa-sina)/(cosa+sina)=(1-tana)/(1+tana)
tana=-1/2,则2*sina-3*sina*cosa-5*(cosa)*(cosa)的值是
若tana=1/2,则(sina+cosa)/(2sina+3cosa)=多少?
已知tana=-(1/3),计算(sina+2cosa)/(5cosa-sina)
求证1+sina-cosa/1+sina+cosa=tana/2
已知tana=2,求值:(1)cosa+sina/cosa-sina
tana=根号2,求cosa+sina/cosa-sina
若tana=1/2则(sina+cosa)/(2sina
为什么sina+cosa/sina-cosa =tana+1/tana-1
已知tana=-1/3,则(sina+2cosa)/(5cosa-sina)等于多少
tanA=-1/3,则5cosA-sinA/sinA+2cosA?