Turn on thread page Beta
 You are Here: Home >< Maths

# C2 Geometry Need Help!!! watch

1. A line L has the equation y=mx and a circle C has equation x²+y²-6x-4y+9=0

a) Given that L is a tangent to C find the possible values of m
b) Find the range of values of m given that L intersects C in two distinct points
c) Find the range of the valuse of m given that L and C do not intersect.
2. rewrite it in the form (x+a)²+(y+b)²+c=0
√c is the radius
(-a,-b) is the centre

Draw out a little picture and it becomes clear that the two possible tangents are at (0,2) or (3,-1), as the line y=mx must pass through the origin.

You can then work out the gradients using
(y one - y two)/(x one - x two) - cant work out how to get subscript...

HTH
3. (Original post by Fenchurch)
A line L has the equation y=mx and a circle C has equation x²+y²-6x-4y+9=0

a) Given that L is a tangent to C find the possible values of m
b) Find the range of values of m given that L intersects C in two distinct points
c) Find the range of the valuse of m given that L and C do not intersect.
completing the square on x²+y²-6x-4y+9=0
is

(x-3)² -9 + (y-2)² -4+9=0
(x-3)²+(y-2)²=4 centre = (3,2)

when x=0

(-3)²+(y-2)²=4
9+y²-4y+4=4
y²-4y+9=0
(y-2)² =2±√5 so 0,2±√5 is one set of co-ordinates

(x-3)²+(y-2)²=4 when y=0

(x-3)²+(-2)²=4
(x-3)²=0
(3,0) for co-ordinate 2

not sure about the value m

Turn on thread page Beta
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: January 27, 2006
Today on TSR

### Which business legend are you?

We have the answer...

### University open days

• University of Bradford
Wed, 21 Nov '18
• Buckinghamshire New University
Wed, 21 Nov '18
• Heriot-Watt University
Wed, 21 Nov '18
Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE