Geometry of the circle. Watch

chatterclaw73
Badges: 8
Rep:
?
#1
Report Thread starter 1 month ago
#1
A circle has its centre at the origin and cuts the x axis at the points A(-c,0) and B(c,0). Write down the equation of the circle.
The point P(h,k) lies on the circle. Find expressions for the gradients of AP and BP. By showing that the products of the gradients is -1, prove that angleAPB=90 degrees.

I have answered most of this question.

The gradients are k/h+c and k/h-c. How do I show the product of the gradients is -1? Thanks for any pointers.
0
reply
mqb2766
Badges: 13
Rep:
?
#2
Report 1 month ago
#2
Multiply and note that the h and k satisfy the equation of a circle?
(Original post by chatterclaw73)
A circle has its centre at the origin and cuts the x axis at the points A(-c,0) and B(c,0). Write down the equation of the circle.
The point P(h,k) lies on the circle. Find expressions for the gradients of AP and BP. By showing that the products of the gradients is -1, prove that angleAPB=90 degrees.

I have answered most of this question.

The gradients are k/h+c and k/h-c. How do I show the product of the gradients is -1? Thanks for any pointers.
0
reply
chatterclaw73
Badges: 8
Rep:
?
#3
Report Thread starter 1 month ago
#3
Thankyou. I feel a bit stupid for not seeing that!!
(Original post by mqb2766)
Multiply and note that the h and k satisfy the equation of a circle?
0
reply
mqb2766
Badges: 13
Rep:
?
#4
Report 1 month ago
#4
Thales won't be sacrificing a bull for you :-)
(Original post by chatterclaw73)
Thankyou. I feel a bit stupid for not seeing that!!
0
reply
chatterclaw73
Badges: 8
Rep:
?
#5
Report Thread starter 1 month ago
#5
Ouch!! That hurts. I will try harder!

(Original post by mqb2766)
Thales won't be sacrificing a bull for you :-)
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

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.

Personalise

University open days

  • SOAS University of London
    Postgraduate Open Day Postgraduate
    Wed, 29 May '19
  • University of Exeter
    Undergraduate Open Day - Penryn Campus Undergraduate
    Thu, 30 May '19
  • Cranfield University
    Cranfield Forensic MSc Programme Open Day Postgraduate
    Fri, 31 May '19

How did your AQA A-level Business Paper 1 go?

Loved the paper - Feeling positive (195)
22.65%
The paper was reasonable (394)
45.76%
Not feeling great about that exam... (158)
18.35%
It was TERRIBLE (114)
13.24%

Watched Threads

View All
Latest
My Feed

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.

Personalise