Write direction cosines of a line parallel to z-axis.


Given


The line is parallel to z- axis.


So the line would be perpendicular to both x-axis and y-axis.


Hence, the angles formed by the line with x-axis & y-axis are 90° and 90° respectively.


Also the angle formed by the line with z-axis is 0°.


The direction cosines of a line are given by, cos α , cos β , cos γ. Where α,β and γ are angles formed by the line with the x,y and z axes respectively.


Here


α = 90°,β = 90° and γ = 0°


α = cos 90°= 0


β = cos 90°= 0


γ = cos 0° = 1


Therefore the direction cosines of the line parallel to z-axis are (0,0,1).




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