Question

Vector Algebra

Answer 1

Write the direction ratio's of the vector a=i + j - 2k and hence calculate its direction cosines

i know the answer ,just want to know how to do it

Answer 2

Do you know what is direction ratios and direction cosines ?

Answer 3

li'l bit

Answer 4

Okay direction of vector is just the direction of the unit vector along A and it is given by $$ dir A = \frac {\vec{A}}{ | \vec{A}|} $$

Answer 5

$$ \text{ Note: } \vec{A} \text{ cannot be null vector } $$

Answer 6

The direction of a space vector in engineering practice often given by it's direction cosines.

Answer 7

So if $$ \vec{A} = ba \vec{i} + b \vec{j} + c \vec{k} $$ be a space vector represented as an origin vector , and let $$\alpha$$, $$\beta $$ and $$\gama$$ be the angles that it makes with i,j,k. then $$ dir A = \cos \alpha \vec{i} + \cos \beta \vec{j} + \cos \gamma \vec{k}$$ The three coefficients are called the direction cosines of $$\vec{A}$$

Answer 8

can you solve it now ?

Answer 9

okayy

Answer 10

not okay .. tell me D :)

Answer 11

so What is direction ratios ?

Answer 12

??

Answer 13

I suggest you take a look at this

http://www3.ul.ie/~mlc/support/Loughborough%20website/chap9/9_3.pdf

Answer 14

ok so here a=1 ,b=1 and c=-2

Answer 15

@Tomas.A: Typo .. OS should introduce typo

Answer 16

@Diyadiya: Yes :D you are brilliant :D

Answer 17

Hey lallalllalla :D

Answer 18

Fooooooool:D:D:D

Answer 19

ok 1 min :D brb

Answer 20

So

Answer 21

so?

Answer 22

is the ratio 1:1:-2 ?

Answer 23

?

Answer 24

Thanks FoolFM :)

Answer 25

Yes it is .. sorry I went to dinner :(