Practicing Success
If P1 and P2 be the lengths of perpendiculars from the origin on the tangent and normal to the curve $x^{2/3}+y^{2/3}=a^{2/3}$ respectively, the value of $4P_1^2+P_2^2$ is: |
$2a^2$ $a^2$ $3a^2$ $\frac{a^2}{2}$ |
$a^2$ |
$x^{2/3}+y^{2/3}=a^{2/3}$. Let $P ≡ (a\cos^3θ, a\sin^3θ)$ be general point on curve. Equation of tangent is : $y\cos θ +x \sin θ=\frac{a}{2}\sin 2θ$ Equation of normal is : $x\cos θ - y\sin θ = a\cos 2θ$ P1 = ⊥ distance of tangent from origin = $\frac{|\frac{a}{2}\sin 2θ|}{\sqrt{\cos^θ+\sin^2θ}}=|\frac{a}{2}\sin 2θ|$ . . . . (i) |