Science:Math Exam Resources/Courses/MATH110/April 2012/Question 01/Statement

The curve below is called a lemniscate; it is given by the equation

$\displaystyle (x^{2}+y^{2})^{2}=18(x^{2}-y^{2})$

Find the equation of the tangent line at the point $(2,{\sqrt {2}})$ and sketch the tangent line.