You are Here: Home >< Maths

# Integration

Announcements Posted on
Last day to win £100 of Amazon vouchers - don't miss out! Take our quick survey to enter 24-10-2016

1. Part C:

the coordinates of N are (0,-168)

to find the area I integrated between x=0 and 4 and that's as far as I got.

In the mark scheme they have found the area of the rectangle and subtracted the area between 0 and 4.

Can someone explain what I'm missing here ?
2. (Original post by Ravster)

Part C:

the coordinates of N are (0,-168)

to find the area I integrated between x=0 and 4 and that's as far as I got.

In the mark scheme they have found the area of the rectangle and subtracted the area between 0 and 4.

Can someone explain what I'm missing here ?

but you need to find the area of the rectangle from O to N to P to 4

integrate to find area under the curve between 0 and 4 like you said then minus area of rectangle by area under the curve
3. (Original post by thefatone)

but you need to find the area of the triangle from O to N to P to 4

integrate to find area under the curve between 0 and 4 like you said then minus area of triangle by area under the curve
A triangle has straight lines. This isn't a straight line. Hence it's not a triangle.
4. (Original post by Zacken)
A triangle has straight lines. This isn't a straight line. Hence it's not a triangle.
good point i'll change it to rectangle
5. (Original post by thefatone)

but you need to find the area of the rectangle from O to N to P to 4

integrate to find area under the curve between 0 and 4 like you said then minus area of rectangle by area under the curve
That's what I don't understand.

By integrating between 0 and 4 aren't we then left with the area of the shaded region?

Why do we need to involve the rectangle?
6. (Original post by Ravster)
That's what I don't understand.

By integrating between 0 and 4 aren't we then left with the area of the shaded region?

Why do we need to involve the rectangle?
No that's the bit you missed, By integrating between 0 and 4 you get the area between the curve and x-axis

involving the rectangle which includes all of the shaded area and the area between the curve and x-axis is what you need
7. (Original post by Ravster)
That's what I don't understand.

By integrating between 0 and 4 aren't we then left with the area of the shaded region?

Why do we need to involve the rectangle?
Nopes... the area that you find via integration is the blue area below.

## 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: May 21, 2016
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