a`2i+j-k and b =1-2j +2k then| a×b| is?
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Step-by-step explanation:
A
.
B
=ABcosθ
or (2
i
^
−2
j
^
−
k
^
).(
i
^
+
j
^
)=ABcosθ
or 2−2=ABcosθ or cosθ=0⇒θ=90
o
ii) Resultant,
R
=
A
+
B
=(2
i
^
−2
j
^
−
k
^
)+(
i
^
+
j
^
)=3
i
^
−
j
^
−
k
^
The projection of resultant on x -axis =
R
.
i
^
=3
iii) Here,
P
+
A
=
j
^
⇒
P
=
j
^
−
A
=
j
^
−(2
i
^
−2
j
^
−
k
^
)=−2
i
^
+3
j
^
+
k
^
Hope its help..
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