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Find the direction cosines of the vector î + 2ĵ - k̂.

  4. None of these.

Answer (Detailed Solution Below)

Option 1 :
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Detailed Solution

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Concept:

The direction cosines of the vector aî + bĵ + ck̂ are given by α = , β =  and γ = .

 

Calculation:

For the given vector î + 2ĵ - k̂, a = 1, b = 2 and  = -1.

The direction cosines of the vector are:

α = , β =  and γ = 

⇒ α = , β =  and γ = 

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