tana-b等于多少

韩包知2192已知tan(a - b)=0.5,tanb= - 1/7,(0<a,b<180),2a - b=?
华询砍18544972858 ______ tan(2a-2b)=2tan(a-b)/{1-[(tan(a-b)^2]}=4/3 tan(2a-b)=[tan(2a-2b)+tanb]/[1-tan(2a-2b)tanb]=1 又因为0<a,b<180°,所以2a-b=45°或225°

韩包知2192已知tan(a - b)=1/2,tanb= - 1/7,且a、b属于(0,派). 求2a - b的值? -
华询砍18544972858 ______ 解:tana=[tan(a-b)+b]=[tan(a-b)+tanb]/[1-tan(a-b)tanb]=(1/2-1/7)/(1+1/2*1/7)=1/3 tan(2a-b)=tan[(a-b)+a]=[tan(a-b)+tana]/[1-tan(a-b)tana]=(1/2+1/3)/(1-1/2*1/3)=1 又a∈(0,π/4) ∴2a∈(0,π/2) b∈(0,π) ∴-b∈(-π,0) ∴2a-b∈(-π,π/2) ∴2a-b=-3π/4或π/4 ∴tan(2a-b)=1

韩包知2192tan(a - b)=1/2,tanb= - 1/7,a,b属于(负派,0),求tan(2a - b)的值 -
华询砍18544972858 ______ 因为A=(A-B)+B tana=tan(a-b b)=[tan(a-b) tanb]/[1-tan(a-b)*tanb] =(1/2-1/7)/(1 1/2*1/7) =1/3 tan(2a-b)=tan(a a-b) =[tana tan(a-b)]/[1-tana*tan(a-b)] =(1/3 1/2)/(1-1/3*1/2) =1 0-1 ,且0

韩包知2192已知a和b均为锐角,cosa=4/5,tan(a - b)= - 1/3,则tanb等于多少 -
华询砍18544972858 ______ cosa=4/5 tana=3/4 tan(a-b)=-1/3 tanb=tan[a-(a-b)] =[tana-tan(a-b)]/[1+tanatan(a-b)] =[3/4+1/3]/(1-1/4) =(13/12)/(3/4) =13/9

韩包知2192已知tana=2. tan(a - b)=-5/3,则tanb=多少???-
华询砍18544972858 ______ tan b = tan ( a- (a-b))=(tana - tan(a-b)) / (1+tana tan(a-b))=(2 + 5/3) / (1 - 10/3)= -11/7

韩包知2192求证tan(A - B)=(tanA - tanB)/(1+tanAtanB) -
华询砍18544972858 ______ 这个本来就是公式推公式 sin(A-B)=sinAcosB-cosAsinB cos(A-B)=cosAcosB+sinAsinB tan(A-B)=(sinAcosB-cosAsinB)/(cosAcosB+sinAsinB) 分子分母同时除以一个cosAcosB得:=(tanA-tanB)/(1+tanAtanB)

韩包知2192A B 为锐角tan(A - B)=sin(2B),求证2tan(2B)=tanA+tanB -
华询砍18544972858 ______ tan(A-B) = (tanA-tanB)/(1+tanAtanB) =sin(2B)=2sinBcosB tanA-tanB=2sinBcosB(1+tanAtanB)= 2sinBcosB+2tanAsin²B tanA(1-2sin²B)= 2sinBcosB+tanB tanA=(2sinBcosB+tanB)/cos(2B) tanA+tanB={sin(2B)+tanB[1+cos(2B)]}/cos(2B)= {sin(2B)+ sin(2B)}/cos(2B)= 2tan(2B)

韩包知2192已知tana=4,tanb=3,则tan(a+b)是多少 -
华询砍18544972858 ______[答案] tan(a+b)=(tana +tanb)/1-tanatanb=(3+4)/1-3x4=-7/11

韩包知2192已知tan(a - b)=1/2,tanb= - 1/7,a b E(0,TT ) , 求(1)tana; (2)2a - b的值
华询砍18544972858 ______ (1)tana=tan[(a-b)-b]=(tan(a-b)-tanb)/(1+tan(a-b)*tanb)=(1/2-1/7)/(1+1/2*1/7)=1/3 (2)tan(2a-b)=tan[(a-b)+a]=(tan(a-b)+tana)/(1-tan(a-b)tana)=(1/2+1/7)/(1-1/2*1/7)=9/13

韩包知2192已知tana tanb是方程2x² - 3x - 7=0的两根,则tan(a+b)等于多少? 请写一下过程 谢谢了! -
华询砍18544972858 ______[答案] tana+tanb=3/2 tana*tanb=-7/2 tan(a+b) =(tana+tanb)/(1-tanatanb) =(3/2)/(9/2) =1/3