हिंदी

Find the equation of the line in vector and in Cartesian form that passes through the point with position vector 2i^-j^+4k^ and is in the direction i^ +2j^-k^.

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प्रश्न

Find the equation of the line in vector and in Cartesian form that passes through the point with position vector `2hati -hatj+4hatk`  and is in the direction `hati + 2hatj - hatk`.

योग
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उत्तर

The required line passes through the given vector point `vec(r_1) = 2hati - hatj + 4hatk` and is parallel to the vector `vecb = hati + 2hatj - hatk`.

∴ Equation of required line `vecr = vec(r_1) + λ vecb`

or `vecr = (2hati - hatj + 4hatk) + λ(hati + 2hatj + hatk)`    ........(i)

Cartesian Equations :

Taking `vecr = xhati + yhatj + zhatk` in equation (i),

`xhati + yhatj + zhatk = (2hati - hatj + 4hatk) + λ (hati + 2hatj - hatk)`

⇒ `xhati + yhatj + zhatk = (2 + λ)hati + (-1 + 2 λ)hatj + (4 -  λ)hatk`

⇒ x = 2 + λ, y = −1 + 2λ, z = 4 − λ

⇒ `(x- 2)/1 = (y + 1)/2 = (z - 4)/-1 = λ`

∴ `(x- 2)/1 = (y + 1)/2 = (z - 4)/-1` is the cartesian equation of the line.

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अध्याय 11: Three Dimensional Geometry - Exercise 11.1 [पृष्ठ ४७७]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 11 Three Dimensional Geometry
Exercise 11.1 | Q 5 | पृष्ठ ४७७

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