1.

Show that the curves `x y=a^2a n dx^2+y^2=2a^2`touch each other

Answer» curves are `xy= a^2`
`x^2 + y^2 = 2a^2`
`x^2 + (a^2/x)^2 = 2a^2`
`x^2 + a^4/x^2 = 2a^2`
`x^4 + a^4 = 2a^2x^2`
`x^4 + a^4 = 2a^2x^2`
`x^4 + a^4 - 2a^2x^2 = 0`
`(x^2 - a^2)^2 = 0`
`x^2 = a^2`
`x= +- a`
now,`xy= a^2`
`xdy/dx + y(1) = 0`
`dy/dx = -y/x = -a/a= m_1`
now, `x^2 + y^T2 = 2a^2`
`2x + 2y dy/dx= 0`
`dy/dx= -x/y=-a/a= -1= m_2`
as,`m_1=m_2`
so, curves are touching each other
hence proved


Discussion

No Comment Found

Related InterviewSolutions