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Find the direction cosine of a line which makes equal angles with the co-ordinate axes. |
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Answer» If l, m, n are the d.c.'s of a line then `l^2+m^2+n^2=1` `therefore cos^2alpha+cos^2alpha+cos^2alpha = 1` `3cos^2alpha = 1` `cos^2alpha=(1)/3 => cosalpha=pm(1)/sqrt5 Thusm the d.c.'s of line are `pm(1)/SQRT3, pm(1)/sqrt3, pm(1)/sqrt3,` |
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