Homework Help

[LiamT988]

Hi guys, i'd really appreciate if you could help with this maths problem:

A circle has equation (x-3)\^2+(y+5)\^2=25

and you have to find where y=kx intersects the circle twice

I'm assuming you use the discrimant and say that K>0 and that you substitute the y=kx into the circle equation however i keep getting the incorrect answer

Thanks

 

[Steven G]

It is great that you have tried to solve this. Good for you. Now can you please show us your work so we know where you need help?

 

[mmm4444bot]

… (x-3)\^2+(y+5)\^2=25 …

… keep getting the incorrect answer …

Please show your work, so that tutors can see what you're doing. Are those two back slashes typos?

Also, check out the forum's submission guidelines; you can start with this summary. Thank you!

?

 

[LiamT988]

Hi, so what I have done is substitute y=kx into the (y-5)^2 part of the circle, so I get (k-5)^2 x then I expand the bracket to get K^2+10k+25 but I’m not sure where to go from here

 

[Steven G]

(k-5)^2 x

No, you did not substitute kx for y in (y-5)^2. Rather you substituted k for y in (y-5)^2 and then you multiplied by x (on the outside).

What to do next? First fix that mistake and write the whole equation...(x-3)^2+rewrite=25. Then solve this equation.

 

[LiamT988]

Hi guys, i'd really appreciate if you could help with this maths problem:



A circle has equation (x-3)^2+(y+5)^2=25



and you have to find where y=kx intersects the circle twice



I'm assuming you use the discrimant and say that K>0 and that you substitute the y=kx into the circle equation however i keep getting the incorrect answer



So far what I have done is input Kx into the equation so I have (kx+5)^2 but from here I am confused


Thanks







​

 

[LiamT988]

No, you did not substitute kx for y in (y-5)^2. Rather you substituted k for y in (y-5)^2.

What to do next? First fix that mistake and write the whole equation...(x-3)^2+rewrite=25. Then solve this equation.

I have figured it out now thank you

 

[Steven G]

Expand, combine and then solve (x-3)^2+(kx+5)^2=25