C4 Parametrics Area Under Curve Watch

TSRforum
Badges: 7
Rep:
?
#1
Report Thread starter 3 years ago
#1
How did I get +24cos(4theta) instead of -24cos(4theta)? Name:  ImageUploadedByStudent Room1464009192.884314.jpg
Views: 52
Size:  106.0 KB
Name:  ImageUploadedByStudent Room1464009214.317830.jpg
Views: 46
Size:  109.2 KB


Posted from TSR Mobile
0
reply
Ano123
Badges: 10
Rep:
?
#2
Report 3 years ago
#2
Could you post the question?
1
reply
Zacken
Badges: 22
Rep:
?
#3
Report 3 years ago
#3
(Original post by TSRforum)
How did I get +24cos(4theta) instead of -24cos(4theta)? Name:  ImageUploadedByStudent Room1464009192.884314.jpg
Views: 52
Size:  106.0 KB
Name:  ImageUploadedByStudent Room1464009214.317830.jpg
Views: 46
Size:  109.2 KB


Posted from TSR Mobile
Several things are wrong.

1. It should be \int_0^{\pi/6} + 48\cdots \, \mathrm{d} \theta

2. \sin \theta \sin 3\theta = \frac{1}{2}(\cos 2x - \cos 4x). i.e: \cos(-2x) = \cos 2x \neq -\cos 2x as you seem to think.
0
reply
TSRforum
Badges: 7
Rep:
?
#4
Report Thread starter 3 years ago
#4
(Original post by Zacken)
Several things are wrong.

1. It should be \int_0^{\pi/6} + 48\cdots \, \mathrm{d} \theta

2. \sin \theta \sin 3\theta = \frac{1}{2}(\cos 2x - \cos 4x). i.e: \cos(-2x) = \cos 2x \neq -\cos 2x as you seem to think.
So when it says (A-B) in the trig identity I should look at that as the difference between A and B?


Posted from TSR Mobile
0
reply
Zacken
Badges: 22
Rep:
?
#5
Report 3 years ago
#5
(Original post by TSRforum)
So when it says (A-B) in the trig identity I should look at that as the difference between A and B?


Posted from TSR Mobile
That's generally what subtraction means, yes.
1
reply
IrrationalRoot
Badges: 18
Rep:
?
#6
Report 3 years ago
#6
(Original post by Zacken)
That's generally what subtraction means, yes.
Not sure, difference of x and y might mean |x-y|.

If by their last post OP means A-B should be taken as |A-B| then yes but only because \cos(x) \equiv \cos(-x).
0
reply
Zacken
Badges: 22
Rep:
?
#7
Report 3 years ago
#7
(Original post by IrrationalRoot)
Not sure, difference of x and y might mean |x-y|.

If by their last post OP means A-B should be taken as |A-B| then yes but only because \cos(x) \equiv \cos(-x).
Good point, I wasn't sure what the OP was asking.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts

All the exam results help you need

1,095

people online now

225,530

students helped last year

University open days

  • Sheffield Hallam University
    Clearing open day Undergraduate
    Tue, 20 Aug '19
  • Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 21 Aug '19
  • University of Dundee
    Undergraduate Open Day Undergraduate
    Mon, 26 Aug '19

Are you going to self-release into Clearing?

Yes I've pressed the button (97)
18.91%
No I'm happy with my uni offer (326)
63.55%
Not yet but I am planning to (24)
4.68%
Not yet but I might (66)
12.87%

Watched Threads

View All
Latest
My Feed