You are Here: Home >< Maths

circle question Watch

1. This question is from Edexcel, June 2010, C2
The circle C has centre A(2,1) and passes through the point B(10, 7) .

(a) Find an equation for C.

The line L1 is the tangent to C at the point B.

(b) Find an equation for L1

The line L2 is parallel to L1 and passes through the mid-point of AB.

Given that intersects C at the points P and Q,

(c) Find the length of PQ, giving your answer in its simplest surd form.
I've done a and b but I don't understand how to get c.
Any help on explaining how to get c would be very much appreciated, thanks
2. Never mind, I've figured it out
3. You've got the equation of L2: Same gradient as L1, and it passes through the midpoint of AB which you can find, plug it in to y-y1=m(x-x1). You know that L2 intersects the circle at 2 points (P&Q), you should be able to see what to do from there.
4. In case anyone googled this to find out how to do part c), here is how I did it:

Hope that helps
5. Turns out I didn't read the question right.. Thanks for the help though

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: February 11, 2014
Today on TSR

What is the latest you've left an assignment

And actually passed?

Simply having a wonderful Christmas time...

Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources
Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.