If a vector 2i + 3j + 8k is perpendicular to the vector 4j - 4i + ak then the value of a is
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Answered by
84
Let a = 2i + 3j + 8k and b = 4j - 4i + ak = -4i + 4j + ak
As a and b are perpendicular to each other then their Dot product os Zero
=> a . b = 0
=> ( 2i + 3j + 8k ) . ( -4i + 4j + ak ) = 0
=> 2 × ( -4 ) + 3 × 4 + 8 × a = 0
=> -8 + 12 + 8a = 0
=> 4 + 8a = 0
=> 8a = -4
=> a = -1 / 2
As a and b are perpendicular to each other then their Dot product os Zero
=> a . b = 0
=> ( 2i + 3j + 8k ) . ( -4i + 4j + ak ) = 0
=> 2 × ( -4 ) + 3 × 4 + 8 × a = 0
=> -8 + 12 + 8a = 0
=> 4 + 8a = 0
=> 8a = -4
=> a = -1 / 2
sweetgirl25:
The answer is not there in option... Method is right but answer is wrong
There may be priting error in the values...i am not sure for the answer..i simply solve the problem by using method...
ya thank you so much
pleasure to hlp you..
answer my second question if possible
Answered by
12
Answer:
answer =-1/2
answer is given in the attachment
Attachments:
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