I'm new at this

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Ok..u may be wondering why I'm asking all these questions and its because I have to complete a calculus packet (i havent took calculus yet)...

A circle is tangent to the y-axis at y=3 and has one x-intercept at x=1..how in the world do u deduce the equation of a circle?
 
general form of equation of circle: (x-a)^2 + (y-b)^2 = r^2
where (a,b) is centre and r is the radius.
I can run through a solution for you but show me what you've done so far.
 
A circle is tangent to the y-axis at y=3 and has one x-intercept at x=1.
Click to expand...
(x-a)^2 + (y-b)^2 = r^2
Click to expand...

Hi, Brit,

Jimi's given you a good hint. Start by drawing yourself a picture: draw an xy graph and label the two points you know, (0,3) and (1,0). Draw a horizontal dotted line at y = 3. Since the circle is tangent to the y-axis at 3, we know the center of the circle must lie somewhere along this dotted line. Since (1,0) is also on the circle, the center must be to the right of the y-axis. Try to sketch in a circle that contains the two points, just to give yourself an idea of what you're looking for. This should help you see that the center of the circle must have 3 for the y-value: C(a,3) Our job is to find that "a" value as well as the radius of the circle.

Now do the math; insert the know points/values into the general form equation. Here's one result:

(x-a)^2 + (y - 3)^2 = r^2 becomes
(0-a)^2 + (3 - 3)^2 = r^2

Can you take over from here?
 
Yea I knew how to do the equation of a circle but to deduce it are u just implying that i make it a smaller circle?
 
i mean i thought to deduce meant smaller...was the result that u gave a deducement of a circle equation?
 
'reduce' means make smaller not 'deduce'. Deduce means to conclude from reasoning. You just need to find the equation of the circle, end of.
 
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