This video is all about a proof of tangent question, and is aimed at GCSE maths grade 7+.
“Prove that x – 2y =10, is a tangent to the circle x² + y² = 20.”
Proof of tangent questions are usually non calculator and generally 4 – 5 marks.
- It’s useful to draw the question first to try to understand what they are asking 🙂
- Proof of tangent means that the straight line touches the circle once, at the circumference
- There will be only one value of x and y for both equations
- Simultaneous equations, with two solutions, are where the line passes through the circle
These types of questions appear in all the main examination boards, including Edexcel, AQA and OCR. They are popular and, once you have the basic principles, fairly similar. Please do stop the video, try the question and compare your solution.
If you would like to find out more try these:
Please do leave a comment below if you are not sure. Alternately you can view my YouTube channel and leave a comment there – I’ll always try to respond as quickly as possible.