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Question
If `veca=hati+2hatj-hatk, vecb=2hati+hatj+hatk and vecc=5hati-4hatj+3hatk` then find the value of `(veca+vecb).vec c`
Solution
`veca=hati+2hatj-hatk, vecb=2hati+hatj+hatk and vecc=5hati-4hatj+3hatk`
`therefore (veca+vecb).vec c`
`=(hati+2hatj-hatk+2hati+hatj+hatk).(5hati-4hatj+3hatk)`
`=(3hati+3hatj).(5hati-4hatj+3hatk)`
=3 x 5+3 x (-4) +0 x 3
=15-12
=3
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