Question #53c2f

1 Answer
Jun 25, 2016

sqrt2x-y-1=0.

Explanation:

Eqn. of Hyperbola : x^2-y^2=1.

Diff. both sides w.r.t. x, 2x-2ydy/dx=0.
:. dy/dx=x/y, y!=0.
:.[dy/dx]_(x=sqrt2,y=1) = sqrt2.
:. Slope of tgt. to Hyp. at pt. (sqrt2,1)=sqrt2, & pt. (sqrt2,1) is on the tgt.

Hence, reqd. eqn. of tgt. is : y-1=sqrt2*(x-sqrt2), writing it in std. form, sqrt2x-y-1=0.

Here, we had to find the eqn. of tgt. using implicit diffn. Otherwise, eqn. of the tgt. line at a pt.(h,k) on Hyp. : x^2-y^2=1, is, hx-ky=1.

Here, pt. (h,k)=(sqrt2,1) is on Hyp. : x^2-y^2=1, since it satisfy the eqn. of Hyp.So, tgt.line is sqrt2x-y=1, as before!