if a and b are two vectors such that |a vector+b vector|=root 29 and a vector cros(2i^+4j^+4k^)=(2i^+4j^+4k^)cross b vector then find the value of (a vector+b vector).(-7i^+2j^+3k^)
Mradul Sharma , 6 Years ago
Grade
1 Answers
Arun
Last Activity: 6 Years ago
Dear student
a x (2, 4, 4) + b x (2,4, 4) = 0
Or we can write
(a+b ) x (2 i + 4j + 4k) = 0
Hence
a + b = p( 2i + 4j + 4k)
Now
As |a +b| = sqrt (29)
4p² + 16p² + 16p² = 29
p² = 29/36
Hence
p = sqrt(29) /6
Now
You can calulate the further question.
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