Ex 10.1

Chapter 10 Class 11 Conic Sections
Serial order wise

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class

### Transcript

Ex 10.1, 8 Find the centre and radius of the circle x2 + y2 – 8x + 10y – 12 = 0 Given x2 + y2 – 8x + 10y – 12 = 0. We need to make this in form (x – h)2 + (y – k)2 = r2 From (1) x2 + y2 – 8x + 10y – 12 = 0 x2 – 8x + y2 + 10y – 12 = 0 (x2 – 8x) + (y2 + 10y) − 12 = 0 [x2 – 2(x)(4)] + [y2 + 2(y)(5)] − 12 = 0 [x2 – 2(x)(4) + 42 − 42] + [y2 + 2(y)(5) + 52 − 52] – 12 = 0 [x2 – 2(x)(4) + 42] + [y2 + 2(y)(5) + 52 ] − 42 − 52 – 12 = 0 Using (a − b)2 = a2 + b2 − 2ab (x – 4)2 + (y + 5)2 − 16 − 25 − 12 = 0 (x – 4)2 + (y + 5)2 = 16 + 25 + 12 (x – 4)2 + (y + 5)2 = 53 (x – 4)2 + (y − (−5))2 = 53 Comparing (2) & (3) h = 4, k = −5 & r2 = 53 r = √53 Centre (h, k) = (4, −5) & Radius = r = √𝟓𝟑

#### Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.