• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

ECAT and MCAT Preparation: Post your doubts here!

Messages
1,477
Reaction score
1,893
Points
173
AoA,
Many of us will be preparing for ECAT and MCAT for various university tests.
In preparation, we would encounter problems, so post your doubts here and others will solve.
JazakAllah!

Helpful things added by different people:

What to study for A level students, added by Slash:
Click here
click here for geometry formulas by @Slash

Playlist for Physics different topics (Very good explanations!)
http://www.youtube.com/playlist?list=PLF71B362214423F9D

http://www.brightstorm.com/science (shared by XPFMember)

Helpful link shared by hassam:
http://www.youtube.com/user/ExamFearVideos

Determinants shared by @hassam

Link shared by HIMYM forever!! (Determinants)
http://tutorial.math.lamar.edu/Classes/LinAlg/DeterminantByRowReduction.aspx

Formula of some metals shared by @hassam

5 * 5 determinants method shared by @smzimran

Rotational Dynamics shared by @hassam


Quadratic equations post by @hassam

Functions, Row echelon and Angular Momentum shared by @hassam




Least count of instruments shared by @hassam
 
Messages
1,477
Reaction score
1,893
Points
173
If Z1 = 1 + i and Z2 = 2 + 3i , then |Z2 - Z1| = ?

My answer is root 5
but the book says its (root 3) i

I dont get it, probably the book is wrong here... :confused:
 
Messages
98
Reaction score
54
Points
18
The book is definitely wrong. I mean they are asking for modulus of the difference of the two given complexes. Modulus is a distance or a magnitude. It cannot have iota (i) with it
 
Messages
1,477
Reaction score
1,893
Points
173
The book is definitely wrong. I mean they are asking for modulus of the difference of the two given complexes. Modulus is a distance or a magnitude. It cannot have iota (i) with it
Exactly, now iam beginning to realise the standard of CIE, atleast the books were never misleading!
 
Messages
1,477
Reaction score
1,893
Points
173
Another one:
The value of x and y when (x + iy)^2 = 5 + 4i

A. x = 2 , y = -1
B. x = -2 , y = 1
C. x = 2 , y = -i
D. x = 2 , y = 2

The book says the answer is A but I think none of the options are correct!
 
Messages
2,619
Reaction score
293
Points
93
smbody solve this
do we need to know determinnat of n by n matrix and n greater than 3.....i meean 4 by 4...and so on....as for inverses....till wat we need to know 2 by 2 and 3 by 3??
 

Attachments

  • km.PNG
    km.PNG
    48.4 KB · Views: 15
Messages
2,619
Reaction score
293
Points
93
This one's pretty simple. The answer is 0
Steps :-
1: Row3 + Row2
2: Row3 + Row1
All elements of Third row become zero so the whole determinant becomes zero
i dint understand ur method.......?.....i learned the method mentioned khan acdemy videos
 
Messages
98
Reaction score
54
Points
18
i dint understand ur method.......?.....i learned the method mentioned khan acdemy videos
You can try your method (expansion of determinant), it'll give the same answer (zero), but it'll take way more time. And in Entry tests you don't have much time to expand the determinant and then find the answer.
And Operations on Rows and columns method is easier plus it wouldn't take more than half a minute.
 
Messages
1,477
Reaction score
1,893
Points
173
You can try your method (expansion of determinant), it'll give the same answer (zero), but it'll take way more time. And in Entry tests you don't have much time to expand the determinant and then find the answer.
And Operations on Rows and columns method is easier plus it wouldn't take more than half a minute.
We are in the learning phase right now, so no shortcuts for now!

We will learn them later!
 
Messages
98
Reaction score
54
Points
18
Equal charges are given to two spheres of different radii. What should be the potential on both?
Equal, right?
 
Messages
1,477
Reaction score
1,893
Points
173
Ah right! K then choose from the given options.
A: more on smaller sphere
B: more on larger sphere
C: equal on both
D: depends on the nature of material of sphere.
It could be both D and A :/
A

capacitance is inversely proportional to potential if charge is constant.

So the sphere with less capacitance (or less radius) will have more potential.
 
Messages
98
Reaction score
54
Points
18
A

capacitance is inversely proportional to potential if charge is constant.

So the sphere with less capacitance (or less radius) will have more potential.
Yeah i get it how the answer could be A. But capaciatance also depends on medium which makes the option D correct as well. =/
 
Top