If xdy - ydx = \(\sqrt{x^2 + y^2}\) dx. If y = y(x) \(\&\) y(1) = 0 then y(3) is :
Two lenses one biconvex and other plano concave have same magnitude of power. The refractive indices of their materials are 1.5 and 1.7 respectively. If the radii of curvature of the lenses are as shown. find the ratio : \(\frac{R_1}{R_2}\) :