Turn on thread page Beta
 You are Here: Home >< Maths

# C4- Vectors watch

1. will upload in a min
2. (Original post by Qer)
will upload in a min

need help in last part

what I am done so far is
they mention that the area is twice .I 3sqroot3 which becomes 6sqroot3
then then I use formula
1/2 (AD)*(SQROOT 24) * Sin30=6sqroot 3
to find AD length

then I try to use modulus here
I set an expression
as D lies on L

(..........)^2=AD (ad=6sqroot 2)
and then take a square to remove sqroot
and get an equ
6lenda^2 -24 lenda-19 =0

(I thought that by doing that I will get two values of lenda and will sub that in
-1+2lenda
lenda-4
6-lenda
3. (Original post by Qer)

need help in last part

what I am done so far is
they mention that the area is twice .I 3sqroot3 which becomes 6sqroot3
then then I use formula
1/2 (AD)*(SQROOT 24) * Sin30=6sqroot 3
to find AD length

then I try to use modulus here
I set an expression
as D lies on L

(..........)^2=AD (ad=6sqroot 2)
and then take a square to remove sqroot
and get an equ
6lenda^2 -24 lenda-19 =0

(I thought that by doing that I will get two values of lenda and will sub that in
-1+2lenda
lenda-4
6-lenda
Could you please upload an image of your working?
4. (Original post by Muttley79)
Could you please upload an image of your working?
I don't have my phone with me now(I am in library and forgot mobile at home .I will upload my working when I will go home...)
thanks for response
5. the height of triangle CDA will be the same as that of triangle CAB.

it follows that the base of triangle CDA must be double that of triangle CAB.... in other words length AD = 2AB

suppose AB were 8 units long. then D could be 16 units away from A so that DAB was a line, or 16 units away from A so that ABD was a line.
6. (Original post by the bear)
the height of triangle CDA will be the same as that of triangle CAB.

it follows that the base of triangle CDA must be double that of triangle CAB.... in other words length AD = 2AB

suppose AB were 8 units long. then D could be 16 units away from A so that DAB was a line, or 16 units away from A so that ABD was a line.
thank you
Finally got right answer

so the whole point is if the area gets double it means it base gets double
7. (Original post by Qer)
thank you
Finally got right answer

so the whole point is if the area gets double it means it base gets double
https://i.imgur.com/XJyemeI.jpg

Reply
Submit reply
Turn on thread page Beta

### Related university courses

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:
Updated: March 1, 2018
Today on TSR

### He lied about his age

Thought he was 19... really he's 14

### University open days

1. University of Bradford
University-wide Postgraduate
Wed, 25 Jul '18
2. University of Buckingham
Psychology Taster Tutorial Undergraduate
Wed, 25 Jul '18
3. Bournemouth University
Clearing Campus Visit Undergraduate
Wed, 1 Aug '18
Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.