jami74
Badges: 11
Rep:
?
#1
Report Thread starter 6 years ago
#1
I am finding areas under curves and know what to do if I have something that looks like y=x^3-x^2-6x for example but I really don't know what to do with brackets. Please can someone talk me through this one?

y=x(x-1)(x+3)

What I want to do is multiply the brackets first like this:

x*x=x2,
x*3=3x,
-1*x=-x
-1*3=-3

And then multiply everything with the x at the front like this:

x*x2=x3,

x*3x=3x2,
x*-x=-x2
x*-3=-3x

Which gives me:

x3
(3x2-x2) 2x2
-3x

y=x3 +2x2 -3x

But I don't think this is right. What am I doing wrong?
1
reply
Mr M
Badges: 20
Rep:
?
#2
Report 6 years ago
#2
It is right (apart from your typo of a 2 instead of a 3 in the final line).
0
reply
TenOfThem
Badges: 16
Rep:
?
#3
Report 6 years ago
#3
(Original post by jami74)




y=x2 +2x2 -3x

But I don't think this is right. What am I doing wrong?
apart from changing a 3 to a 2 you are correct
0
reply
jami74
Badges: 11
Rep:
?
#4
Report Thread starter 6 years ago
#4
(Original post by Mr M)
It is right (apart from your typo of a 2 instead of a 3 in the final line).

(Original post by TenOfThem)
apart from changing a 3 to a 2 you are correct
Seriously? Thank-you.
Can I try another one?
0
reply
Mr M
Badges: 20
Rep:
?
#5
Report 6 years ago
#5
(Original post by jami74)
Seriously? Thank-you.
Can I try another one?
You can check your work yourself here.
1
reply
jami74
Badges: 11
Rep:
?
#6
Report Thread starter 6 years ago
#6
(Original post by Mr M)
You can check your work yourself here.
Thank-you Mr M
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
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

  • The University of Law
    The Bar Series: Applications and Interviews - London Bloomsbury campus Postgraduate
    Thu, 17 Oct '19
  • Cardiff Metropolitan University
    Undergraduate Open Day - Llandaff Campus Undergraduate
    Sat, 19 Oct '19
  • Coventry University
    Undergraduate Open Day Undergraduate
    Sat, 19 Oct '19

How has the start of this academic year been for you?

Loving it - gonna be a great year (140)
17.86%
It's just nice to be back! (212)
27.04%
Not great so far... (281)
35.84%
I want to drop out! (151)
19.26%

Watched Threads

View All