Home
Class 12
MATHS
If the line x=y=z intersect the line s i...

If the line `x=y=z` intersect the line `s in Adotx+s in Bdoty+s in Cdotz=2d^2,s in2Adotx+s in2Bdoty+s in2Cdotz=d^2,` then find the value of `sinA/2dotsinB/2dotsinC/2w h e r eA ,B ,C` are the angles of a triangle.

Text Solution

Verified by Experts

Any point on the line `x = y =z` is `(lamda, lamda, lamda)`
This point lies on the planes
`" "sinA*x+sinB*y+sinC*z=2d^(2)`
and `" "sin2A*x+sin2B*y+sin 2C*z=d^(2)`
`therefore" "sinA lamda+sin Blamda+sinC lamda = 2d^(2)`
and `" "sin2A lamda+sin 2B lamda +sin 2C lamda =d^(2)`
Eliminating `d^(2)`, we get
`" "sinA+sinB+sinC=2(sin2A+2sin2B+sin2C)`
or `" "4cos""(A)/(2) cos ""(B)/(2) cos""(C)/(2)=8sin A sin B sin C`
or `" "sin""(A)/(2)sin""(B)/(2)sin""(C)/(2)=(1)/(16)`
Promotional Banner

Topper's Solved these Questions

  • THREE-DIMENSIONAL GEOMETRY

    CENGAGE|Exercise Exercise 3.1|12 Videos
  • THREE-DIMENSIONAL GEOMETRY

    CENGAGE|Exercise Exercise 3.2|15 Videos
  • THREE DIMENSIONAL GEOMETRY

    CENGAGE|Exercise Question Bank|20 Videos
  • TRIGNOMETRIC RATIOS IDENTITIES AND TRIGNOMETRIC EQUATIONS

    CENGAGE|Exercise Question Bank|34 Videos

Similar Questions

Explore conceptually related problems

In DeltaABC if 2s =a +b+c and (s-b)(s-c)=x" sin"^(2)(A)/(2) ,then the value of x is

The lines 3x+4y=9&4x-3y+12=0 intersect at Pdot The first line intersects x-a xi s at A and the second line intersects y-a xi s at Bdot Then the circumradius of the triangle P A B is 3/2 (b) 5/2 (c) 10 (d) none

If a/(sinA)=K , then the area of "DeltaA B C" in terms of K and sines of the angles is (K^2)/4s in A\ s in B\ s in C (b) (K^2)/2s in A\ s in B\ s in C 2K^2s in A\ s in B\ "sin"(A+B) (d) none

In a scalene triangle A B C ,D is a point on the side A B such that C D^2=A D D B , sin s in A S in B=sin^2C/2 then prove that CD is internal bisector of /_Cdot

The distance between the lines x=1-4t, y=2+t, z=3+2t" and "x=1+s, y=4-2s, z=-1+s is

If a + b+ c =2s , thent the value of (s-a)^(2) + (s-b)^(2) +( s-c)^2 will be

In triangle ABC, sin((A)/(2))sin((C)/(2))=sin((B)/(2)) and '2s' is the perimeter of the triangle. Then the value of s is

Let A B C be a triangle right-angled at Aa n dS be its circumcircle. Let S_1 be the circle touching the lines A B and A C and the circle S internally. Further, let S_2 be the circle touching the lines A B and A C produced and the circle S externally. If r_1 and r_2 are the radii of the circles S_1 and S_2 , respectively, show that r_1r_2=4 area ( A B C)dot

In the shown fig. S1 and S2 are two identical coher- ent sources of sound, separated by a distance d. A receiver moves along the line XY (which is parallel to line S1 S2) to detect the intensity of sound at various points on the line. Distance of line XY from line S1 S2 is D (gt gt d) . Point O is the foot of perpendicular bisector of the line S1 S2 on XY. Distance of first intensity maxima (on line XY) measured from O is y. Find percentage change in value of y if the temperature of air increases by 1%.

CENGAGE-THREE-DIMENSIONAL GEOMETRY -JEE Previous Year
  1. If the line x=y=z intersect the line s in Adotx+s in Bdoty+s in Cdotz=...

    Text Solution

    |

  2. (i) Find the equation of the plane passing through the points(2,1,0...

    Text Solution

    |

  3. Find the equation of a plane passing through (1, 1, 1) and parallel to...

    Text Solution

    |

  4. A parallelepiped S has base points A ,B ,Ca n dD and upper face points...

    Text Solution

    |

  5. Find the equation of the plane containing the lines 2x-y+z-3=0,3x+y+z=...

    Text Solution

    |

  6. A line with positive direction cosines passes through the point P(2, –...

    Text Solution

    |

  7. The value of k such that (x-4)/1=(y-2)/1=(z-k)/2 lies in the plane 2x-...

    Text Solution

    |

  8. If the lines (x-1)/2=(y+1)/3=(z-1)/4 and (x-3)/1=(y-k)/2=z/1 intersect...

    Text Solution

    |

  9. A variable plane at distance of 1 unit from the origin cuts the coordi...

    Text Solution

    |

  10. A plane passes through (1,-2,1) and is perpendicualr to two planes 2x...

    Text Solution

    |

  11. Let P(3,2,6) be a point in space and Q be a point on line vec r=( hat...

    Text Solution

    |

  12. Equation of the plane containing the straight line x/2=y/3=z/4 and per...

    Text Solution

    |

  13. If the distance of the point P(1,-2,1) from the plane x+2y-2z=alpha...

    Text Solution

    |

  14. The point P is the intersection of the straight line joining the point...

    Text Solution

    |

  15. Perpendiculars are drawn from points on the line (x+2)/2=(y+1)/(-1)=z...

    Text Solution

    |

  16. Two lines L1x=5, y/(3-alpha)=z/(-2)a n dL2: x=alphay/(-1)=z/(2-alpha) ...

    Text Solution

    |

  17. A line l passing through the origin is perpendicular to the lines l1: ...

    Text Solution

    |

  18. let L be a straight line passing through the origin. Suppose that all ...

    Text Solution

    |

  19. In R^(3), consider the planes P(1):y=0 and P(2),x+z=1. Let P(3) be a p...

    Text Solution

    |

  20. Consider the planes 3x-6y-2z=15a n d2x+y-2z=5. Statement 1:The parame...

    Text Solution

    |

  21. Consider three planes P(1):x-y+z=1 P(2):x+y-z=-1 and " "P...

    Text Solution

    |