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# C2 help needed Watch

1. Given that the line with the equation y=x+k is a tangent to the circle x^2+y^2=25

Find the 2 possible values of K

Need help getting started with this question
2. (Original post by Vorsah)
Given that the line with the equation y=x+k is a tangent to the circle x^2+y^2=25

Find the 2 possible values of K

Need help getting started with this question
Substitute in. Remember that you have a tangent if the discriminant is zero
3. (Original post by Vorsah)
Given that the line with the equation y=x+k is a tangent to the circle x^2+y^2=25

Find the 2 possible values of K

Need help getting started with this question
Do you have the answer to this question?

I got +- 50 as k by solving the equations simultaneously and then letting b^2 - 4ac be 0
4. (Original post by Lunch_Box)
Do you have the answer to this question?

I got +- 50 as k by solving the equations simultaneously and then letting b^2 - 4ac be 0
Check your working, that isn't right but you are close!
5. (Original post by Lunch_Box)
Do you have the answer to this question?

I got +- 50 as k by solving the equations simultaneously and then letting b^2 - 4ac be 0

Probably a typo

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