Maths, Addmaths and Statistics: Post your doubts here!

P

PhyZac

Messages
681
Reaction score
1,731
Points
153
Zoya Shahab said:
Without using a calculator evaluate
(lg 5)^2+lg2 lg50
Click to expand...

(lg 5)^2 + lg2 lg 50
(lg 5)^2 + lg2 lg(2 * 25)
(lg 5)^2 + lg2 (lg 2 + lg25)
(lg 5)^2 + lg2 (lg 2 + lg 5^2)
(lg 5)^2 + lg 2 ( lg 2 + 2log 5)
(lg 5)^2 + lg2*log2 + 2*log2*log5
(lg 5)^2 +2*lg2*lg5 + (log2)^2 [Now you can notice the form a^2 + 2ab + b^2 = (a+b)^2
[lg5 +lg2]^2
(lg(5*2))^2
(lg10)^2
1^2
1
 
H

Hamza0909

Messages
3
Reaction score
0
Points
11
Anyone can post the Nov 2012 Maths paper for O levels please....? secondly, make x the subject of formula.. x(x-2)=t-2
Thanks.
 
F

flora16

Messages
2
Reaction score
0
Points
11
hey! i want some help...
i need past papers/links from before 2000 along with there er and ms
plz help!
thnx.
 
T

tdk

Messages
113
Reaction score
28
Points
38
Thnx a lot. I have a doubt here:
If a measurement is reported as 7 mm rounded to nearest mm, then its lower limit is obviously 6.50 mm but what is its upper limit? Is it 7.49 or 7.50?
 
P

PhyZac

Messages
681
Reaction score
1,731
Points
153
tdk said:
Thnx a lot. I have a doubt here:
If a measurement is reported as 7 mm rounded to nearest mm, then its lower limit is obviously 6.50 mm but what is its upper limit? Is it 7.49 or 7.50?
Click to expand...
Asslamu Alikum Wa Rahmatullah Wa Barakatoho

7.5
because the actual lower limit is 7.499999999999....so when you round you get 7.5
But it is usually written in the form
7.5>x>=6.5 ( read as: xis less than 7.5 and more than or equal to 6.5)
 
Suchal Riaz

Suchal Riaz

Messages
1,983
Reaction score
3,044
Points
273
tdk said:
Thnx a lot. I have a doubt here:
If a measurement is reported as 7 mm rounded to nearest mm, then its lower limit is obviously 6.50 mm but what is its upper limit? Is it 7.49 or 7.50?
Click to expand...
let me tell u an easy method. they say nearest to 'a' millimeter. mean 1 millimeter. divide 1 by 2. u get 0.5 millimeter. add it to the real value u get upper bound and subtract it u get lower bound.
for example is they say 1245m to the nearest 5 m. divide by 2 u get 2.5 add it u get 1247.5 cm as upper bound. subtract u get 1242.5 as lower bound.
if u have gud concept of it u can just do it by looking at it but sometimes u have confusion so use this method rather than guess.
 
Haris Bin Zahid

Haris Bin Zahid

Messages
492
Reaction score
399
Points
73
Please I need full explanation of this relative velocity question:
A coastguard station receives a distress call from a ship which is travelling at 15 km/h on a bearing of 150°. A lifeboat leaves the coastguard station at 15 00 hours; at this time the ship is at a distance of 30 km on a bearing of 270°. The lifeboat travels in a straight line at constant speed and reaches the ship at 15 40 hours.
(i) Find the speed of the lifeboat.
(ii) Find the bearing on which the lifeboat travelled.

PhyZac , scouserlfc , FAHMEED
 
P

PhyZac

Messages
681
Reaction score
1,731
Points
153
Haris Bin Zahid said:
Please I need full explanation of this relative velocity question:
A coastguard station receives a distress call from a ship which is travelling at 15 km/h on a bearing of 150°. A lifeboat leaves the coastguard station at 15 00 hours; at this time the ship is at a distance of 30 km on a bearing of 270°. The lifeboat travels in a straight line at constant speed and reaches the ship at 15 40 hours.
(i) Find the speed of the lifeboat.
(ii) Find the bearing on which the lifeboat travelled.

PhyZac , scouserlfc , FAHMEED
Click to expand...
Assalamu Alikum
What are the answers?

Is the speed 60 km/h and bearing 310?
 
Zoya Shahab

Zoya Shahab

Messages
135
Reaction score
114
Points
43
Given that lg 2=a and lg3=b and that lg x=3a-4b+1 find x.
Express lg cube root 972 in terms of a and b.
 
You must log in or register to reply here.
Top