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प्रश्न
If the direction cosines of a line are `(1/c, 1/c, 1/c)` then ______.
विकल्प
0 < c < 1
c = ± 3
c > 2
c > 0
`c = ±sqrt(3)`
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उत्तर
If the direction cosines of a line are `(1/c, 1/c, 1/c)` then `underlinebb(c = ±sqrt(3))`
Explanation:
Since d. c. of line are `{1/c, 1/c, 1/c}`
∴ `1/c^2 + 1/c^2 + 1/c^2` = 1
`\implies` c2 = 3
`\implies c = ±sqrt(3)`
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