{"id":9888,"date":"2022-01-31T21:54:57","date_gmt":"2022-01-31T16:24:57","guid":{"rendered":"https:\/\/mathemerize.com\/?p=9888"},"modified":"2022-01-31T21:56:03","modified_gmt":"2022-01-31T16:26:03","slug":"pole-and-polar-of-a-circle-equation","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/pole-and-polar-of-a-circle-equation\/","title":{"rendered":"Pole and Polar of a Circle Equation"},"content":{"rendered":"
Here you will learn what is the pole and polar of a circle and pole of given line with respect to a circle.<\/p>\n
Let’s begin –<\/p>\n
Let any straight line through the given point A\\((x_1, y_1)\\) intersects the given circle S = 0 in two points P and Q and if the tangent of the circle at P and Q meet at the point R then the locus of point R is called polar of point A<\/strong> and point A is called the pole<\/strong>, with respect to the given circle.<\/p>\n The equation of the polar of point \\((x_1, y_1)\\) with respect to circle \\(x^2 + y^2\\) = \\(a^2\\) is<\/p>\n \\(xx_1 + yy_1\\) = \\(a^2\\)<\/p><\/blockquote>\n Proof<\/strong> : Let APQ is a chord given in figure which passes through the point A\\((x_1, y_1)\\) which intersects the circle at points P and Q and the tangents are drawn at points P and Q meet at point R (h, k) then the equation of PQ the chord of contact<\/a> is \\(x_1h + y_1k\\) = \\(a^2\\)<\/p>\n \\(\\therefore\\)\u00a0 Locus of point S(h, k) is \\(xx_1 + yy_1\\) = \\(a^2\\)\u00a0 which is the equation of the polar.<\/p>\n Note<\/strong> :<\/p>\n (i)\u00a0 If point is outside the circle then the equation of polar and chord of contact<\/a> is same. So the chord of contact is polar.<\/p>\n (ii)\u00a0 If point is inside the circle then chord of contact<\/a> does not exist but polar exist.<\/p>\nEquation of the Polar of Point<\/h2>\n