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Grade 12th passVectors

If magnitude of vector a is 2 and magnitude of vector b is 5 and magnitude of a × b is 8 then what is the value of vector ab is equal to???

Profile image of Suhas
7 Years agoGrade 12th pass
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1 Answer

Profile image of Arun
7 Years ago

|AxB| = |A|*|B|*sin #

Where # is the angle between the two vectors.

Hence, sin # = |AxB| / (|A|*|B|) = 8/10

Hence, cos # = √(1-(8/10)²) = 6/10 or 3/5

|A|.|B| = |A|*|B|*cos # = 2*5*(3/5) = 6