You are Here: Home >< Maths

# Finding the gradient - Parametric equations - SOLVED

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. Need some help guys

Question

The parametric equations of a curve are x=2t^2 and y=4t. Two points on the curve are P(2p^2,4p) and Q(2q^2,4q)

Show that the gradient of the chord joining the points P and Q is 2/(p+q)

So i tried by finding the gradient by using y step over x step and i did not get anything like 2/(p+q)

This is a 2 mark question, so it must be something simple:/

BTW this is part B of the question

part a was .. show that the gradient of the normal to the curve at P is -P (I got that right)..
2. Once you have your expression, factorise (difference of two squares)
3. Your method is correct, what did you do. Post your working so we can find the mistake. Remember that x^2-y^2=(x+y)(x-y)
4. you know the gradient is: [4p-4q]/[2p^2-2q^2] = [4(p-q)]/2(p+q)(p-q)]

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: June 3, 2012
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:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams