Locus of a centriod of the triangle whose vertices are $(a \cos t, a \sin t),(b \sin t,-b \cos t)$ and $(1…
Locus of a centriod of the triangle whose vertices are $(a \cos t, a \sin t),(b \sin t,-b \cos t)$ and $(1,0)$, where $t$ is a parameter, is
-
$(3 x+1)^2+(3 y)^2=a^2-b^2$
-
$(3 x-1)^2+(3 y)^2=a^2-b^2$
-
$(3 x-1)^2+(3 y)^2=a^2+b^2$
-
$(3 x+1)^2+(3 y)^2=a^2+b^2$
Solution
$x=\frac{\cos t+b \sin t+1}{3} \Rightarrow a \cos t+b \sin t=3 x-1$
$y=\frac{a \sin t-b \cos t}{3} \Rightarrow a \sin t-b \sin t=3 y$
Squaring \& adding, $(3 \mathrm{x}-1)^2+(3 \mathrm{y})^2=\mathrm{a}^2+\mathrm{b}^2$
Asked in: JEE Main 2003
Practice more Straight Lines questions on Aicharya