若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
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若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?若sin(a+b)=1/2,sin(a-b)
若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
sin(a+b)=sinacosb+cosasinb=1/2
sin(a-b)=sinacosb-cosasinb=1/3
联立--->sinacosb=5/12,cosasinb=1/12
相除--->tana/tanb=5
在△ABC中,求证;sin^(A/2)+sin^(B/2)+sin^(C/2)=1-2sin(A/2)sin(B/2)sin(C/2)
3 在三角形ABC中,已知(a2+b2)sin(A-B)=(a2-b2)sin(A+B) 求证:ABC是等腰或直角三角形(a^2+b^2)sin(A-B)=(a^2-b^2)sin(A+B),(sin^A+sin^B)sin(A-B)=(sin^A-sin^B)sin(A+B) sin^A*(sin(A+B)-sin(A-B))=sin^B*(sin(A-B)+sin(A+B)) sin^A*2c
懂得进.证明,sina+sin(a+b)+sin(a+2b)+...sin(a+nb)=sin(a+ab/2)sin[(n+1)b/2]/sin(b/2)
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在三角形ABC中,若(a^2+b^2)sin(A-B)=(a^2-b^2)sin(A+B),则三角形是?a/sinA=b/sinB=k则a=ksinA,b=ksinB代入(a^2+b^2)sin(A-B)=(a^2-b^2)sinC并把k约分(sin²A+sin²B)sin(A-B)=(sin²A-sin²B)sin(A+B) sin²A*[sin(A+B)-sin(A-B)
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若sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
sin(a-b)=sin(a+b)吗?
sin(a-b)=?
证明sina sin(a+2b) - sinb sin(b+2a) =sin(a+b)sin(a-b)