हिंदी

Find the shortest distance between the lines whose vector equations are r→=(1-t)i^+(t-2)j^+(3-2t)k^ and r→=(s+1)i^+(2s+1)k^. - Mathematics

Advertisements
Advertisements

प्रश्न

Find the shortest distance between the lines whose vector equations are `vecr = (1-t)hati + (t - 2)hatj + (3 -2t)hatk` and `vecr = (s+1)hati + (2s + 1)hatk`.

योग
Advertisements

उत्तर

Equations of given lines

`vecr = (1 - t)hati + (t - 2)hatj + (3 - 2t)hatk` 

or `vecr = hati - 2hatj + 3hatk + t (-hati + hatj - 2hatk)`

and `vecr = (s + 1)hati + (2s - 1)hatj + (2s + 1)hatk`

or `vecr = hati - hatj + hatk + s (hati + 2hatj - 2hatk)`

Comparing the above equations with `vecr = vec(a_1) + λvec(b_1)` and `vecr = vec(a_2) +µvec(b_2)`,

`vec(a_1) = hati - 2hatj + 3hatk, vec(b_1) = - hati + hatj - 2hatk`

and `vec(a_2) = hati - hatj - hatk, vec(b_2) = hati + 2hatj - 2hatk`

∴ `vec(a_2)  - vec(a_1) = (hati - hatj - hatk) - (hati - 2hatj + 3hatk) = hatj - 4hatk`

`vec(b_1) xx vec(b_2) = (- hati + hatj - 2hatk) xx (hati + 2hatj - 2hatk)`

= `|(hati, hatj, hatk), (-1, 1, -2), (1, 2, -2)|`

= `(-2 + 4)hati - (2 + 2)hatj + (-2 -1)hatk`

= `2hati - 4hati - 3hatk`

∴ `|vec(b_1) xx vec(b_2)|`

= `sqrt((2)^2 + (-4)^2 + (-3)^2)`

= `sqrt(4 + 16 + 9)`

= `sqrt29`

∴ Required minimum distance d = `|((vec(a_2) - vec(a_1)). (vec(b_1) xx vec(b_2)))/|vec(b_1) xx vec(b_2)||`

= `|((hatj - 4hatk). (2hati - 4hatj - 3hatk))/sqrt29|`

= `|(-4 + 12)/sqrt29|`

= `8/sqrt29`

Hence, the minimum distance between the given lines is `8/sqrt29`.

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 11: Three Dimensional Geometry - Exercise 11.2 [पृष्ठ ४७८]

APPEARS IN

एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 11 Three Dimensional Geometry
Exercise 11.2 | Q 17 | पृष्ठ ४७८

संबंधित प्रश्न

Find the shortest distance between the lines

`bar r = (4 hat i - hat j) + lambda(hat i + 2 hat j - 3 hat k)`

and

`bar r = (hat i - hat j + 2 hat k) + mu(hat i + 4 hat j -5 hat k)`

where λ and μ are parameters

 

Show that the following two lines are coplanar:

`(x−a+d)/(α−δ)= (y−a)/α=(z−a−d)/(α+δ) and (x−b+c)/(β−γ)=(y−b)/β=(z−b−c)/(β+γ)`


 

Show that lines: 

`vecr=hati+hatj+hatk+lambda(hati-hat+hatk)`

`vecr=4hatj+2hatk+mu(2hati-hatj+3hatk)` are coplanar 

Also, find the equation of the plane containing these lines.

 

Find the distance between the planes 2x - y +  2z = 5 and 5x - 2.5y + 5z = 20


Find the shortest distance between the lines: 

`vecr = (hati+2hatj+hatk) + lambda(hati-hatj+hatk)` and `vecr = 2hati - hatj - hatk + mu(2hati + hatj + 2hatk)`


Find the shortest distance between the lines.

`(x + 1)/7 = (y + 1)/(- 6) = (z + 1)/1` and `(x - 3)/1 = (y - 5)/(- 2) = (z - 7)/1`.


Find the shortest distance between the lines whose vector equations are `vecr = (hati + 2hatj + 3hatk) + lambda(hati - 3hatj + 2hatk)` and `vecr = 4hati + 5hatj + 6hatk + mu(2hati + 3hatj + hatk)`.


Find the shortest distance between lines `vecr = 6hati + 2hatj + 2hatk + lambda(hati - 2hatj + 2hatk)` and `vecr =-4hati - hatk + mu(3hati - 2hatj - 2hatk)`.


Find the shortest distance between the lines `(x+1)/7=(y+1)/(-6)=(z+1)/1 and (x-3)/1=(y-5)/(-2)=(z-7)/1`


Find the shortest distance between the lines `vecr = (4hati - hatj) + lambda(hati+2hatj-3hatk)` and `vecr = (hati - hatj + 2hatk) + mu(2hati + 4hatj - 5hatk)`


Find the shortest distance between the lines `vec r = hat i + 2hat j + 3 hat k +  lambda(2 hat i +  3hatj +  4hatk)` and `vec r =  2hat i +  4 hat j + 5 hat k +  mu (4hat i + 6 hat j +  8 hat k)`


Find the shortest distance between the lines

\[\frac{x - 2}{- 1} = \frac{y - 5}{2} = \frac{z - 0}{3} \text{ and }  \frac{x - 0}{2} = \frac{y + 1}{- 1} = \frac{z - 1}{2} .\]
 

Find the shortest distance between the lines

\[\frac{x - 1}{2} = \frac{y - 3}{4} = \frac{z + 2}{1}\] and
\[3x - y - 2z + 4 = 0 = 2x + y + z + 1\]
 

Find the shortest distance between the lines given by `vec"r" = (8 + 3lambdahat"i" - (9 + 16lambda)hat"j" + (10 + 7lambda)hat"k"` and `vec"r" = 15hat"i" + 29hat"j" + 5hat"k" + mu(3hat"i" + 8hat"j" - 5hat"k")`


The fuel cost per hour for running a train is proportional to the square of the speed it generates in km per hour. If the fuel costs ₹ 48 per hour at a speed of 16 km per hour and the fixed charges to run the train amount to ₹ 1200 per hour. Assume the speed of the train as v km/h.

Given that the fuel cost per hour is k times the square of the speed the train generates in km/h, the value of k is:


The fuel cost per hour for running a train is proportional to the square of the speed it generates in km per hour. If the fuel costs ₹ 48 per hour at a speed of 16 km per hour and the fixed charges to run the train amount to ₹ 1200 per hour. Assume the speed of the train as v km/h.

The most economical speed to run the train is:


The fuel cost per hour for running a train is proportional to the square of the speed it generates in km per hour. If the fuel costs ₹ 48 per hour at a speed of 16 km per hour and the fixed charges to run the train amount to ₹ 1200 per hour. Assume the speed of the train as v km/h.

The fuel cost for the train to travel 500 km at the most economical speed is:


The fuel cost per hour for running a train is proportional to the square of the speed it generates in km per hour. If the fuel costs ₹ 48 per hour at a speed of 16 km per hour and the fixed charges to run the train amount to ₹ 1200 per hour. Assume the speed of the train as v km/h.

The total cost of the train to travel 500 km at the most economical speed is:


Find the shortest distance between the following lines:

`vecr = (hati + hatj - hatk) + s(2hati + hatj + hatk)`

`vecr = (hati + hatj - 2hatk) + t(4hati + 2hatj + 2hatk)`


Determine the distance from the origin to the plane in the following case x + y + z = 1


The planes `2x - y + 4z` = 5 and `5x - 2.5y + 10z` = 6


Find the shortest distance between the lines, `vecr = 6hati + 2hatj + 2hatk + lambda(hati - 2hatj + 2hatk)` and `vecr = - 4hati - hatk + mu(3hati - 2hatj - 2hatk)`


Read the following passage and answer the questions given below.

Two motorcycles A and B are running at the speed more than the allowed speed on the roads represented by the lines `vecr = λ(hati + 2hatj - hatk)` and `vecr = (3hati + 3hatj) + μ(2hati + hatj + hatk)` respectively.

Based on the above information, answer the following questions:

  1. Find the shortest distance between the given lines.
  2. Find the point at which the motorcycles may collide.

The largest value of a, for which the perpendicular distance of the plane containing the lines `vec"r" = (hat"i" + hat"j") + λ(hat"i" + "a"hat"j" - hat"k")` and `vec"r" = (hat"i" + hat"j") + μ(-hat"i" + hat"j" - "a"hat"k")` from the point (2, 1, 4) is `sqrt(3)`, is ______.


If the shortest distance between the lines `(x - 1)/2 = (y - 2)/3 = (z - 3)/λ` and `(x - 2)/1 = (y - 4)/4 = (z - 5)/5` is `1/sqrt(3)`, then the sum of all possible values of λ is ______.


The shortest distance between the z-axis and the line x + y + 2z – 3 = 0 = 2x + 3y + 4z – 4, is ______.


Find the distance between the lines:

`vecr = (hati + 2hatj - 4hatk) + λ(2hati + 3hatj + 6hatk)`;

`vecr = (3hati + 3hatj - 5hatk) + μ(4hati + 6hatj + 12hatk)`


An aeroplane is flying along the line `vecr = λ(hati - hatj + hatk)`; where 'λ' is a scalar and another aeroplane is flying along the line `vecr = hati - hatj + μ(-2hatj + hatk)`; where 'μ' is a scalar. At what points on the lines should they reach, so that the distance between them is the shortest? Find the shortest possible distance between them.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×