Example  2 - Find equation circle centre (-3, 2) radius 4 - Circle

Example  2 - Chapter 11 Class 11 Conic Sections - Part 2


Transcript

Example 2 Find the equation of the circle with centre (–3, 2) and radius 4. We know that equation of a circle is (x­ – h)2 + (y ­– k)2 = r2 Where (h, k) is the centre & r is the radius Here Centre (h, k) = (–3, 2) So h = −3 & k = 2 & radius (r) = 4. Putting values in (1) (x − (−3))2 + (y – 2)2 = (4)2 (x + 3)2 + (y – 2)2 = 16 (x2 + 32 + 6x) + (y2 + 22 − 4y) = 16 x2 + 9 + 6x + y2 + 4 – 4y = 16 x2 + y2 + 6x – 4y + 13 = 16 x2 + y2 + 6x – 4y + 13 − 16 = 0 x2 + y2 + 6x – 4y − 3 = 0 Hence required equation of circle is x2 + y2 + 6x – 4y − 3 = 0

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.