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Question 471422:  write the equation of hyperbola c entered in (2,1) with foci (2,-3) and (2,5) and asymptote y=x-1 
 Answer by lwsshak3(11628)      (Show Source): 
You can  put this solution on YOUR website! write the equation of hyperbola centered in (2,1) with foci (2,-3) and (2,5) and asymptote y=x-1 
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This is a  hyperbola with vertical transverse axis.Could tell from coordinates of Foci. 
Standard form of hyperbola with vertical transverse axis: (y-k)^2/a^2-(x-h)^2/b^2=1 
From equation of asymptote, y=x-1, its slope, m=1, and y-intercept=-1 
a/b=m=1 
a=b 
c=4 (Could also tell from coordinates of Foci.) 
c^2=a^2+b^2=a^2+a^2=2a^2 
16=2a^2 
a^2=16/2=8 
a=√8 
a^2=8 
b^2=8 
Equation: 
(y-1)^2/8-(x-2)^2/8=1 
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Asymptotes: 
y=x-1 (given) 
Other asymptote: y=-mx+b 
Use (x,y) coordinates of center to find b 
1=-1(2)+b 
b=3 
equation of 2nd asymptote: y=-x+3 
see graph below as a visual check on the answer 
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y=±(8+(x-2)^2)^.5+1
 
  
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