Home
Class 12
MATHS
Find the angle between the following pai...

Find the angle between the following pair of lines: A lines with direction ratios 2,2,1 A line joning (3,1,4)to (7,2,12)

A

`cos^(-1)""(2/3)`

B

`cos^(-1)""(3/2)`

C

`tan^(-1)""(-2/3)`

D

`sin^(-1)""(2/3)`

Text Solution

Verified by Experts

The correct Answer is:
A

Given DR's 2,2,1
The DR's of the line joining (2,1,4) to (7,2,12) are 7,-3,2-1,12-44,1,8
`costheta=(4xx2+1xx2+8xx1)/(sqrt(4^2+1^2+8^2)sqrt(2^2+2^2+1^2))`
`=(18)/(sqrt(81)sqrt(9))=(18)/(9xx3)`
`costheta=2/3rArrtheta=cos^(-1)(2/3)`
Promotional Banner

Topper's Solved these Questions

  • THREE DIMENSIONAL GEOMETRY

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise MHT CET Corner|3 Videos
  • THREE DIMENSIONAL GEOMETRY

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise MHT CET Corner|3 Videos
  • STRAIGHT LINE

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise EXERCISE 2(MISCELLANEOUS PROBLEMS)|30 Videos
  • TRIGONOMETRIC FUNCTIONS

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise EXERCISE 2 (MISCELLANEOUS PROBLEMS)|26 Videos

Similar Questions

Explore conceptually related problems

Find the angle between the following pair of lines whose direction ratios are given 1,2,3 and 2,-4,4

Find the angle between the following pair of lines whose direction ratios are given -1,2,1and 2,3,-1

Find the angle between the pairs of lines with direction ratio proportional to: 2, 2, 1 and 4, 1, 8

The angle between a line with direction ratios proportional to 2, 2, 1 and a line joining (3, 1, 4) and (7, 2, 12) is

Find the angle between the pairs of lines with direction ratio proportional to: 1, 2, -2, and -2, 2, 1

The acute angle between the two lines with direction ratios (1,-2,-2) and (2,-2,1) is

Find the angle between the pairs of lines with direction ratio proportional to: 5, -12, 13 and -3, 4, 5

If the angle between the lines with direction ratios 2, -1, 1 and 1, k, 2 is 60^(@) , then k =

If the angle between the lines with direction ratios a, 3, 5 and 2, -1, 2 is 45^(@) , then a =

Find the angle between the lines whose direction ratios are: 2,-3,4 and 1,2,1 .

MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS-THREE DIMENSIONAL GEOMETRY-Exercise 2 (MISCELLANEOUS PROBLEMS)
  1. If OA is equally inclined to OX,OY ,OZ and if A is sqrt(3) units from ...

    Text Solution

    |

  2. If P(0,1,2),Q(4,-2,1) and O(0,0,0) are three points, then /POQ=

    Text Solution

    |

  3. A line makes the same angle theta with each of the x and z-axes. If t...

    Text Solution

    |

  4. If the directions cosines of a vector of magnitude 3 are (2/3,(-a)/3,2...

    Text Solution

    |

  5. If 1/2,1/3,n are direction cosines of a line, then the value of n is

    Text Solution

    |

  6. A line makes an angle theta both with x-axis and y-axis. A possible ra...

    Text Solution

    |

  7. The direction cosines to two lines at right angles are (1,2,3) and (-2...

    Text Solution

    |

  8. A line makes acute angles of alpha,beta and gamma with the coordinate ...

    Text Solution

    |

  9. The direction rations of the diagonals of a cube which joins the origi...

    Text Solution

    |

  10. The projection of the line segment joining (2,5,6) and (3,2,7) on the ...

    Text Solution

    |

  11. In DeltaABC the mid points of the sides AB, BC and CA are (l, 0, 0),...

    Text Solution

    |

  12. The diection cosines of two lines are proportional to (2,3,-6) and (3,...

    Text Solution

    |

  13. The angle between the lines whose direction cosines are (sqrt3/4,1/4,s...

    Text Solution

    |

  14. Let O be the origin and P be the point at a distance 3 units from orig...

    Text Solution

    |

  15. If the points A(2,3,-4), B(1,-2,3) and C(3,lambda,-1) are colliner, th...

    Text Solution

    |

  16. If the directions cosines of a straight line are ltk,k,kgt then

    Text Solution

    |

  17. Find the angle between the following pair of lines: A lines with direc...

    Text Solution

    |

  18. If P(p), Q(q), R(r) and S(s) be four points such that 3p+8q=6r+5s then...

    Text Solution

    |

  19. The direction cosines of line joining (1,-1,1) and (-1,1,1) are

    Text Solution

    |

  20. A vector r is inclined at equal angles to OX,OY and OZ If the magnitud...

    Text Solution

    |