Question

if a,b and c are the angles made by any vector with x,y and z axis respectively then find the value of cos^2a+cos^2b-sin^2c

Answer 1

As you should know: sin^2c=1-cos^2c
Then substituting this inot the equation:
cos^2a+cos^2b-(1-cos^2c)=cos^2a+cos^2b+cos^2c-1
Thn another identity: cos^2a+cos^2b+cos^2c=1
So the result is =0

Answer 2

but how cos^2a+cos^2b+cos^2c=1

Answer 3

hmmm...

Answer 4

no i m not gud in drawing

Answer 5

can u sort it out 4 me

Answer 6

@terenzreignz help him, please, I don't know

Answer 7

Me neither :3
Me and vectors don't get along T.T
@hartnn ?

Answer 8

plsssss....anybody just help me out