Question

Equation of diameter of circle x^2+y^2+2x-4y=4 that is parallel to 3x+5y=4 is

Answer 1

Step-by-step explanation:

We need to find the centre of the circle.

=> x² + 2x + y² - 4y = 4

=> (x + 1)² + (y - 2)² = 4 + 1 + 4 = 9

i.e. centre (-1,2)

The line can be written as 5y = 4 - 3x

i.e. y = 4/5 - 3x/5..........i.e. gradient -3/5

so, equation is y - 2 = (-3/5)(x + 1)

=> 5(y - 2) = -3x - 3

i.e. 5y + 3x - 7 = 0

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