Equation for a Tangent Circle on the Y-Axis at (3,7)

[john560]

Homework Statement

Write an equation for the circle centered on the y-axis and is tangent to a vertical line at the point (3,7)

Homework Equations

The Attempt at a Solution

(x^2)/9 + (y-7)/9

 

[Mentallic]

Homework Statement

Write an equation for the circle centered on the y-axis and is tangent to a vertical line at the point (3,7)

Homework Equations

The Attempt at a Solution

(x^2)/9 + (y-7)/9

Sorry to sound rude, but what the hell kind of attempt is that? There is so much wrong with it that... ahh what's the point...

First start with the basics. Do you know the general formula for a circle with centre (h,k) and radius r?

 

[john560]

Yes, I do know the basic formula for a circle.

 

[Mentallic]

Right my apologies, you just missed the (y-7)² and didn't make it equal to 1.

 

[tiny-tim]

welcome to pf!

hi john560! welcome to pf!

(try using the X² icon just above the Reply box )

Write an equation for the circle centered on the y-axis and is tangent to a vertical line at the point (3,7)
…
(x^2)/9 + (y-7)/9

i] that isn't an equation, is it?

ii] anyway, it looks like a parabola, not a circle

try again ​

 

[john560]

Yea i forgot to square the Y side and make it equal to one

Right my apologies, you just missed the (y-7)² and didn't make it equal to 1.

(x²)/9 + (y-7)²/9 =1

 

[eumyang]

Yea i forgot to square the Y side

(x²)/9 + (y-7²)/9 =1

Not quite. This is what I'm seeing:
$$\frac{x^2}{9}+\frac{y-7^2}{9}=1$$
Is that what you really mean? (Look carefully at the 2nd fraction.)

 

[tiny-tim]

Yea i forgot to square the Y side and make it equal to one





(x²)/9 + (y-7²)/9 =1

Yup!

(except the ² is the wrong side of the bracket, and some professors would prefer you to multiply throughout by 9 )

 

[john560]

$$\frac{x^2}{9} + \frac{(y-7)^2}{9}=1$$

 

[Mentallic]

Yep, that's it

But like tiny-tim said, it is usually more appropriate to have the circle equation in the form $$(x-h)^2+(y-k)^2=r^2$$ rather than $$\frac{(x-h)^2}{r^2}+\frac{(y-k)^2}{r^2}=1$$

 

[john560]

(except the ² is the wrong side of the bracket, and some professors would prefer you to multiply throughout by 9 )

So that's what he meant$$\frac{x^2}{3^2} + \frac{(y-7)^2}{3^2}=1$$

Thank you guys, wish this site had a thumbs up icon so i could show my appreciation that way.

 

[tiny-tim]

now how did i do that?