tan(a+b)=2/5 ,tan(a+π/4)=3/22 ,那么tan(b-π/4)等于?

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tan(a+b)=2/5 ,tan(a+π/4)=3/22 ,那么tan(b-π/4)等于?
tan(a+b)=2/5 ,tan(a+π/4)=3/22 ,那么tan(b-π/4)等于?

tan(a+b)=2/5 ,tan(a+π/4)=3/22 ,那么tan(b-π/4)等于?
令x=tan(b-π/4)
y=tan(a+π/4)=3/22
tan(a+b)=tan[(a+π/4)+(b-π/4)]=2/5
所以(x+y)/(1-xy)=2/5
2-3x/11=5x+15/22
tan(b-π/4)=x=4

z=a+bi
ab∈R
则a²+b²-3i(a+bi)-1-3i=0
(a²+b²+3b-1)-3ai-3i=0
所以a²+b²+3b-1=0
-3a-3=0
a=-1
则1+b²+3b-1=0
b=0,b=-3
所以z=-1,z=-1-3i