Pls solve this question i need it
Q.11. If a   a n d   b are unit vectors, then what is the angle between a   a n d   b so that 3 a - b may be a unit vector..

Dear Student,


a and b are unit vectorshence a and b=1Let 3a-b is also a unit vectorthen 3a-b=1squaring both we get3a-b2=13a2+b2-23a.b=13a2+b2-23a.b=13a2+b2-23a.b=1since a.b=abcosθHence we get3a2+b2-23a.b×cosθ=1 a and b=13+1-23×cosθ=123×cosθ=3cosθ=323cosθ=32but cos 30=32Hence θ=30°
Regards,

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