1THIS SOUNDS RIDICULOUS
WHEN I DELETE THE QUESTIONS U GUYS COMPLAIN NOT TO DELETE SI THAT U CAN MAKE AN ATTEMPT TO SOLVE!
AND NOW THESE QUESTIONS HAVE BEEN UP FOR SO LONG AND NO ONE EVEN ATTEMPTED A SINGLE ONE!
SEEMS LIKE FORUM IS JUST FOR "MAKING BIG WORDS" AND "SHOWING OFF THEIR IDEALISM"..THAT'S IT!
I HOPE I AM WRONG...BUT THIS IS WHAT I FEEL!
23and thats what i m trying to say , study at home , ye websites wagere bohot kam kaam ate hai !!
btw for first m vector is on the line AC
position vector of any point on line AC will be of the form
r=a + λ (c - a )
if this pt is m , then (c - a).(b - m) = 0
frm this find λ , and hemce m vector
will post other answers l8r gtg now
232nd is easy
(axb)xc = - [ c x (axb)] = cx (bxa) = (c.a)b - c.b(a)
so u got a.c and b.c
ax(bxc) = (a.c)b - (a.b)c
u got a.c , a.b is given , so u can find the ans now
23ax(axc) = b
i.e (a.c)a - (a2)c = b
a.c = |a||c|cosθ = 2cosθ
so 2acosθ - c = b
square both sides and u wll get an eqn only with cosθ
234.
let a and b be the 2 given vectors
a = i+j+2k
b=i+2j+k
any vector r coplanar with these 2 vectors can be written as
r= λa+μb
now r.(i+j+k)=0
so λ + μ +λ+2μ +2λ + μ =0
so λ=-μ
so r =λ (a-b)=λ(k-j)
hence any vector of the form λ(k-j) is the required ans where λ = any real no
now since they hav asked for unit vector , u kno wat λ shud be
btw us question me b and c option are one and the same LoL
23for 5th , c option is automatically rulled out , since |BC| = |A|
also , option a is a vector , hence it cannot be bc vector.
option b is d vector, since a+d=0, so d= -a , and option b is -a vector
hence none of these
