यदि |a|=10, |b|=2 तथा a.b=12 है तो `|axxb|` का मान है

Options

A. 16
B. 256
C. `-16`
D. `-256`

Answer

A

Explanation

यहाँ `|a|=10,|b|=2 a.b=12` [दिया है]
`therefore |a xx b|=|a| |b| sin theta`
`therefore |a xx b|^(2)=|a|^(2) |b|^(2) sin^(2) theta`
` =|a|^(2) |b|^(2)(1-cos^(2)theta)`
` =|a|^(2) |b|^(2)|a|^(2) |b|^(2) cos^(2)theta`
` =|a|^(2) |b|^(2)-(a.b)^(2)` `[therefore a.b=|a||b| cos theta]`
`=100xx4-144=256`
`|a xx b|=16`