Posted by alk on Sunday, August 3, 2008 at 11:30am.
Well, if it is tangent to the y axis at (0,3), then the center must be somewhere on the horizontal line y = 3 because the radius is perpendicular to the tangent.
So if center is at (a,3)
(x-a)^2 + (y-3)^2 = r^2
we know when x = 0, y = 3 so
a^2 = r^2
so
(x-a)^2 + (y-3)^2 = a^2
now when y = 0, x = 1 and something else
(1-a)^2 +9 = a^2
1 -2a +a^2 +9 = a^2
a = 5 = r
so center is at (5,3)
(x-5)^2 + (y-3)^2 = 25
is the equation
x intercepts:
(x-5)^2 +9 = 25
x^2 - 10 x + 25 + 9 = 25
x^2 -10 x = -9
x^2 - 10 x + 25 = 16
(x-5)^2 = 16
x-5 = +/- 4
x = 1 or x = 9
which you could have seen from a sketch once you knew the radius was 5 and the center at (5,3)
Related Questions
calc - a circle is tangent to the y-axis at y=3 and has one x-intercept at x=1 1...
Math - A circle is tangent to the y-axis at y=3 and has one x-intercept at x=1, ...
math - a circle is tangent to the y-axis at y=3 and has one x-intercept at x=1 a...
Algebra: Check please!!! - 1. Find the x-intercept and the y-intercept of 8x - ...
Algebra: x and y intercept, someone check please - 1. Find the x-intercept and ...
College Algebra - 1.The graph of y = - 1/2 |x - 5| - 3 can be obtained from the ...
math - find a function y=ax^2+bx+c whose graph has an x-intercept of 1, a y-...
Quadratic Equations and Functions - I started having trouble on part (c), and I ...
Math - Find the equation of the circle that passes through the origin and x-...
Quadratic Equations and Functions - I started having trouble on part (c), and I ...
For Further Reading
