Home
Class 12
MATHS
Show that the vector hat(i) +hat(j)+hat(...

Show that the vector `hat(i) +hat(j)+hat(k)` is equally inclined to the axes OX,OY and OZ.

Text Solution

Verified by Experts

Let `a=hat(i)+hat(j)+hat(k)`.
Then ,magnitude of vector `a=|a|=sqrt(1^2+1^2+1^2)=sqrt(3)`
Therefore , the direction consines of are `(x).(|a|),(y)/(|a|),(z)/(|a|) i.e.,(1)/(sqrt(3)),(1)/(sqrt(3)),(1)/(sqrt(3))`.
If a makes angles a,b and r respectively with (postive) OX,OY and OZ.
Then , we have `cos alpha =1 sqrt(3)`.
(`because` Direction cosines are the cosines of the angles made by `hat(i),hat(j),hat(k)` components of the vector with X,Y and Z axes)
`cos beta=(1)/(3) and cos gamma =(1)/(3),alpha=beta=gamma=cos^(-1)((1)/(sqrt(3)))`.
Promotional Banner

Topper's Solved these Questions

  • VECTOR ALGEBRA

    SUBHASH PUBLICATION|Exercise TRY YOURSELF|4 Videos
  • VECTOR ALGEBRA

    SUBHASH PUBLICATION|Exercise TRY YOURSELF|4 Videos
  • TRIANGLES

    SUBHASH PUBLICATION|Exercise Exercise 5.7|1 Videos

Similar Questions

Explore conceptually related problems

Show that the direction cosines of a vector equally inclined to the axes OX,OY and OZ are +-((1)/(sqrt(3)),(1)/(sqrt(3)),(1)/(sqrt(3))) .

Write the projection of the vector hat(i) + hat(j) + hat(k) along the vector hat(j) .

Show that the vectors bar(a) = 2 hat(i) - 3 hat(j) + 4 hat(k) and bar(b) = -4 hat(i) + 6 hat(j) - 8k are collinear.

Show that the vectors 2hat(i)-3hat(j)+4hat(k) and -4hat(i)+6hat(j)-8hat(k) are collinear.

The value of p such that the vectors hat(i) + 3hat(j) - 2hat(k), 2hat(i) - hat(j) + 4hat(k) and 3hat(i) + 2hat(j) + p hat(k) are coplanar is

The scalar product of the vector vec(a) = hat(i) + hat(j) + hat(k) with a unit vector along the sum of vectors vec(b) = 2hat(i) + 4hat(j) - 5hat(k) and vec(c ) = lambda hat(i) + 2hat(j) + 3hat(k) is equal to one. Find the value of lambda and hence find the unit vector along vec(b) + vec(c ) .

Show that the vectors 2hat(i)-hat(j)+hat(k),hat(i)-3hat(j) . And 3hat(i)-4hat(j)-3hat(k) . Form the vertices of a right angled triangle.

Find the sine of the angle between the vectors hat(i) + 2 hat(j) + 2 hat(k) and 3 hat(i) + 2 hat(j) + 6 hat(k)

Write the projection of the vector 7hat(i) + hat(j) - 4hat(k) on the vector 2hat(i) + 6hat(j) + 3hat(k) .

Write a vector in the direction of the vector hat(i) - 2hat(j) + 2hat(k) that has magnitude 9 units.

SUBHASH PUBLICATION-VECTOR ALGEBRA -TWO MARKS/THREE MARKS QUESTIONS WITH ANSWERS
  1. Find the direction cosines of the vector hati +2hatj + 3hatk

    Text Solution

    |

  2. Find the direction cosines of the vector joining the points A(1,2,-3) ...

    Text Solution

    |

  3. Show that the vector hat(i) +hat(j)+hat(k) is equally inclined to the ...

    Text Solution

    |

  4. Find the position vectors of a point R which divides the line joining ...

    Text Solution

    |

  5. Find the position vector of the mid-point of the vector joining point ...

    Text Solution

    |

  6. Show that the points A, B and C with position vectors , vec(a)=3hat(i)...

    Text Solution

    |

  7. Find the angle between two vectors a and b with magnitudes sqrt(3) and...

    Text Solution

    |

  8. Find the angle between the vectors hat(i)-2hat(j)+3hat(k) and 3hat(i)-...

    Text Solution

    |

  9. Find the projection of the vector hat(i)-hat(j) on the vector hat(i)+h...

    Text Solution

    |

  10. Find the projection of the vector hat(i)+3hat(j)+7hat(k) on the vector...

    Text Solution

    |

  11. Find |vec(a)| and |vec(b)|, if (vec(a)+vec(b)).(vec(a)-vec(b))=8 and |...

    Text Solution

    |

  12. Evaluate the product (3vec(a)-5vec(b)).(2vec(a)+7vec(b)).

    Text Solution

    |

  13. Find the magnitude of two vectors vec(a) and vec(b) having the same ma...

    Text Solution

    |

  14. Find |x|, if for a unit vector a, (vec(x)-vec(a)).(vec(x)+vec(a))=12.

    Text Solution

    |

  15. If a=2hat(i)+2hat(j)+3hat(k),b=hat(i)+2hat(j)+hat(k) and c=3hat(i)+hat...

    Text Solution

    |

  16. Show that |a|b+|b| a is perpendicular to |a|b-|b| a for any two non- z...

    Text Solution

    |

  17. If a,b,c are unit vectors such that a+b+c=0, then find the value of a....

    Text Solution

    |

  18. If either a=0,b=0, then a.b=0. But the converse need not to be true . ...

    Text Solution

    |

  19. If the vertices A,B,C of a triangle ABC have position vectors (1,2,3),...

    Text Solution

    |

  20. Show that the points A(1,2,7),B(2,6,3) and C(3,10,-10 are collinear.

    Text Solution

    |