Home
Class 12
MATHS
If a line makes angle alpha, beta and ga...

If a line makes angle `alpha, beta` and `gamma` with the axes respectively then `sin^(2)alpha+sin^(2)beta+sin^(2)gamma=`

A

1

B

2

C

3

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
B

We have
`l=cos alpha, m=cos beta` and `n=cos gamma`
`:.l^(2)+m^(2)+n^(2)=1`
`impliescos^(2)alpha+cos^(2)beta+cos^(2)gamma=1`
`implies1-sin^(2)alpha+sin^(2)beta+1-sin^(2)gamma=1`
`impliessin^(2)alpha+sin^(2)beta+sin^(2)gamma=2`
Promotional Banner

Topper's Solved these Questions

  • THREE DIMENSIONAL COORDINATE SYSTEM

    OBJECTIVE RD SHARMA|Exercise Section I - Solved Mcqs|16 Videos
  • THREE DIMENSIONAL COORDINATE SYSTEM

    OBJECTIVE RD SHARMA|Exercise Exercise|22 Videos
  • TANGENTS AND NORMALS

    OBJECTIVE RD SHARMA|Exercise Chapter Test|25 Videos
  • TRIGONOMETRIC EQUATIONS AND INEQUATIONS

    OBJECTIVE RD SHARMA|Exercise Chapter Test|60 Videos

Similar Questions

Explore conceptually related problems

Vector vecP angle alpha,beta and gamma with the x,y and z axes respectively. Then sin^(2)alpha+sin^(2)beta+sin^(2)gamma=

If a line makes angle alpha, beta and gamma with the coordinate axes respectively, then cos2alpha+cos 2 beta+cos 2gamma=

If vec(A) makes an angle alpha, beta and gamma from x,y and z axis respectively then sin^(2)alpha+sin^(2) beta+sin^(2) gamma=

If a line makes angles alpha, beta, gamma with the coordinate axes, prove that sin^2alpha+sin^2beta+sin^2gamma=2

If a vector makes angles alpha,beta,gamma with OX, OY and OZ respectively, prove that sin^(2)alpha+sin^(2)beta+sin^(2)gamma=2

If a line makes angles alpha , beta ,gamma with coordinate axes , then sin ^2 alpha +sin^2 beta + sin^2 gamma ………

If a vector makes angle alpha,beta,gamma with ox,or and OZ respectively,then write the value of sin^(2)alpha+sin^(2)beta+sin^(2)gamma

A line makes an angle alpha, beta, gamma, delta with the four diagonals of a cube, then sin^(2)alpha+sin^(2)beta+sin^(2)gamma+sin^(2)delta=

If a vector vec(P) making angles alpha, beta, gamma respectively with the X,Y, and Z axes respectively. Then sin^(2)theta+sin^(2)beta+sin^(2)gamma=

OBJECTIVE RD SHARMA-THREE DIMENSIONAL COORDINATE SYSTEM -Exercise
  1. If a line makes angle alpha, beta and gamma with the axes respectively...

    Text Solution

    |

  2. If the x-coordinate of a point P on the join of Q(2,2,1) and R(5,1,-2)...

    Text Solution

    |

  3. The distance of the point P(a,b,c) from the x-axis is

    Text Solution

    |

  4. Ratio in which the xy-plane divides the joint of (1,2,3) and (4,2,1), ...

    Text Solution

    |

  5. If P(3,2,-4),Q(5,4,-6) and R(9,8,-10) are collinear, then R divides PQ...

    Text Solution

    |

  6. A(3,2,0),B(5,3,2),(-9,6,-3) are the vertices of /\ ABC and AD is the b...

    Text Solution

    |

  7. A line passes through the points (6,-7,-1)a n d(2,-3,1)dot Find te ...

    Text Solution

    |

  8. If a line makes angles alpha,beta,gamma with the positive direction of...

    Text Solution

    |

  9. If P is a point in space such that OP=12 and vec(OP) is inclied at ang...

    Text Solution

    |

  10. A vector vec O P is inclined to O Xa t45^0a n dO Ya t60^0 . Find the ...

    Text Solution

    |

  11. A vector vecr is equally inclined with the coordinates axes. If the ti...

    Text Solution

    |

  12. If vecr is a vector of magnitude 21 and has direction ratios proporti...

    Text Solution

    |

  13. The direction cosines of the lines bisecting the angle between the lin...

    Text Solution

    |

  14. Find the coordinates of the foot of the perpendicular drawn from po...

    Text Solution

    |

  15. The foot of the perpendicular drawn from a point with position vector ...

    Text Solution

    |

  16. The projections of a directed line segment on the coordinate axes are ...

    Text Solution

    |

  17. Let l1,m1,n1; l2,m2,n2 and l3,m3,n3 be the direction cosines of three ...

    Text Solution

    |

  18. If P(x ,y ,z) is a point on the line segment joining Q(2,2,4)a n d ...

    Text Solution

    |

  19. If O is the origin, O P=3 with direction ratios -1,2,a n d-2, then fin...

    Text Solution

    |

  20. A mirror and a source of light are situated at the origin O and at ...

    Text Solution

    |

  21. Find the angel between any two diagonals of a cube.

    Text Solution

    |