numerical that is bothering me.
 

If A = A_1^i + A_2 i + A_3 j and B = B_1 i + B_2 j + B_3 k, then prove that A,B = A_(1 ) B_1 + A_2 B_2 + A_3 A_3
Somebody please solve it and also which type of numerical is this.

Its a simple vector numerical.
1. Multiply A with B and i*i=-1 j*j=-1
2. Then take magnitude and the statement will be proved.

[IMG][URL=http://s163.photobucket.com/user/Erfan_Mushtaq/media/11256417_10206556172884535_624791760_n_zpsywzxftwl.jpg.html][IMG]http://i163.photobucket.com/albums/t306/Erfan_Mushtaq/11256417_10206556172884535_624791760_n_zpsywzxftwl.jpg[/IMG][/URL][/IMG]

@ love reflector

u sure one can write i squared and j squared? aren't they vectors which require to be written as i.i and j.j?

Solution
 

[IMG]http://i.imgur.com/J83pCVU.jpg[/IMG]

Please use the vector notation. Furthermore, iota-squared = -1 is an incorrect notion here in this context. Please do not solve it the way you have done in FSc or, maybe, in A-levels.

"i" has nothing to do with iota. It is just a direction vector(unit vector) along the x-axis.

Regards.

Sorry my mistake and dear just take the magnitude rest is ok.:angle

well i think vectors are cross products and scalers are dot products. mentioned wrongly in above paper

Dot/Cross products
 

[QUOTE=doctorali;839941]well i think vectors are cross products and scalers are dot products. mentioned wrongly in above paper[/QUOTE]

What!? Vectors are cross products, and scalars are dot products!?

Sorry buddy! You have taken vectors and scalars wrongly!

Please come out of the FSc/A-level's physics; otherwise, you score will be ruined for sure!

Regards.

[QUOTE=lovereflector;828678][IMG][URL=http://s163.photobucket.com/user/Erfan_Mushtaq/media/11256417_10206556172884535_624791760_n_zpsywzxftwl.jpg.html][IMG]http://i163.photobucket.com/albums/t306/Erfan_Mushtaq/11256417_10206556172884535_624791760_n_zpsywzxftwl.jpg[/IMG][/URL][/IMG][/QUOTE]

Bro, at the end where you have taken the magnitude needs your attention. You cannot cancel the squared-power of each term with the (1/2) of square-root isolately. You are violating the rules of squareroot.