Date | May 2011 | Marks available | 2 | Reference code | 11M.1.hl.TZ2.7 |
Level | HL only | Paper | 1 | Time zone | TZ2 |
Command term | Find | Question number | 7 | Adapted from | N/A |
Question
The diagram shows a tangent, (TP) , to the circle with centre O and radius r . The size of P^OA is θ radians.
Find the area of triangle AOP in terms of r and θ .
Find the area of triangle POT in terms of r and θ .
Using your results from part (a) and part (b), show that sinθ<θ<tanθ .
Markscheme
area of AOP=12r2sinθ A1
[1 mark]
TP=rtanθ (M1)
area of POT =12r(rtanθ)
=12r2tanθ A1
[2 marks]
area of sector OAP =12r2θ A1
area of triangle OAP < area of sector OAP < area of triangle POT R1
12r2sinθ<12r2θ<12r2tanθ
sinθ<θ<tanθ AG
[2 marks]
Examiners report
The majority of candidates were able to find the area of Triangle AOP correctly. Most were then able to get an expression for the other triangle. In the final section, few saw the connection between the area of the sector and the relationship.
The majority of candidates were able to find the area of Triangle AOP correctly. Most were then able to get an expression for the other triangle. In the final section, few saw the connection between the area of the sector and the relationship.
The majority of candidates were able to find the area of Triangle AOP correctly. Most were then able to get an expression for the other triangle. In the final section, few saw the connection between the area of the sector and the relationship.