Q. 75.0( 1 Vote )

# Find the angles a

(i) Let, r = î - j + k̂

The direction ratios of the vector r = 1, - 1, 1

And, |r | = √ ((1)2 + ( - 1)2 + (1)2)

= √3

The direction cosines of the vector r  So,      Thus, angles made by with the coordinate axes are given by (ii) Let, r = 0 î + j - k̂

The direction ratios of the vector r = 0, 1, - 1

And, |r | = √ ((0)2 + (1)2 + ( - 1)2)

= √2

The direction cosines of the vector r  So,          Thus, angles made by with the coordinate axes are given by (iii) Let, r = 4î + 8 j + k̂

The direction ratios of the vector r = 4, 8, 1

And, |r | = √ ((4)2 + (8)2 + (1)2)

= √81

= 9

The direction cosines of the vector r  So,      Thus, angles made by with the coordinate axes are given by Rate this question :

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