 # Find the minimum distance between the curves y^2 = x-1 and x^2 = y-1                                   please give detail  solution Badiuddin askIITians.ismu Expert
148 Points
13 years ago

Dear Amrit pal both curve are mirror image to each other about y=x

shortaset distance between these two corve is the segment made by line AB which is perpendicular to both the curve at point A and B respectively

as well as line AB is perpendicular to line y=x ,

i.e  slope of line AB is -1

let a general point A is(t2 ,t22 +1)  and point B is (t12 +1 ,t1)

slope of curve x2 =y-1 at A is  dy/dx = 2x

so slope for perpendicular at point A is -1/2x =-1/2t2

it will be equal to -1

-1/2t2 =-1

t2 =1/2

somilerly slope of perpendiculat on y2 =x-1 at point B is  = -2t1

-2t1 = -1

t1=1/2

so poins A and B become ( 1/2 ,5/4) and B is (5/4,1/2)

now find the distance between these two point.

So the minimum distance is (3/4) *√ 2

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