1.

The foot of the perpendicular form `(2,4,-1)` to the line `x +5 =(1)/(4) (y+3) = -(1)/(9) (z - 6)` isA. `(-4,1,-3)`B. `(4,-1,-3)`C. `(-4,-1,3)`D. `(-4,-1,3)`

Answer» Correct Answer - A
Given , `(x +5)/(1) = (y+3)/(4) = (z-6)/(-9) = lambda`
Any point on the line `P(lambda - 5, 4lambda - 3, -9lambda + 6)`
`therefore` Direction ratio of line PQ are.
`(lambda - 5 -2,4lambda,-3-4, - 9lambda + 6+1)`
` = (lambda - 7, 4lambda - 7, - 9lambda + 7)`
`therefore ` PQ is perpendicular to the given line
`because 1(lambda - 7) + 4(4lambda - 7) - 9(-9lambda + 7) = 0`
`rArr lambda - 7 + 16lambda - 28 + 81lambda - 63 = 0`
`rArr " "lambda = 1`
`because` The coordinate of foot of perpendicular are `(-4,1,-3)`


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