tan(x+π/4)=-1/7求tanx

tan(x+π/4)=-1/7求tanx
tan(x+π/4)=-1/7求tanx

tan(x+π/4)=-1/7求tanx
tan(x+π/4)
=(tanx+tanπ/4)/(1-tanxtanπ/4)
=(tanx+1)/(1-tanx)=-1/7
1-tanx=-7tanx-7
tanx=-4/3

tan x = -4/3
过程：tan (x+π/4)=(tan x+ tan π/4)/(1-tan x*tanπ/4)
=(tanx+1)/(1-tanx)
=-1/7
所以，tan x =-4/3