find the centre and radius of the circle x^2+y^2-4x+10y-21=0
Answers
Answered by
15
Step-by-step explanation:
Completing square of x and y:
=> x² + y² - 4x + 10y - 21 = 0
=> (x² - 4x) + (y² + 10y) - 21 = 0
=> (x² - 2(2x) + 2² - 2²) + (y² + 2(5y) + 5² - 5²) - 21 = 0
=> ((x - 2)² - 2²) + ((y + 5)² - 5²) - 21 = 0
=> (x - 2)² + (y + 5)² - 4 - 25 - 21 = 0
=> (x - 2)² + (y -(-5))² = 50
=> √(x - 2)² + (y -(-5))² = √50
Compare this with the standard equation of circle, we get centre is (2, -5) and radius is √50 = 5√2.
Similar questions