Home
Class 12
MATHS
If A + B + C = (3pi)/2, then cos 2A + co...

If `A + B + C = (3pi)/2`, then `cos 2A + cos 2B + cos 2C` is equal to (A) 1 - 4 cos A cos B cos C(B) 4 sin A sin B sin C(C) 1 + 2 cos A cos B cos C(D) 1-4 sin A sin B sin C

A

1-4 cos A cos B cosC

B

4 sin A sin B sin C

C

1+2 cos A cos B cos C

D

1-4 sin A sin B sin C

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Topper's Solved these Questions

  • TRIGNOMETRIC RATIOS & IDENTITIES

    MOTION|Exercise Exercise 2(Level -I)|36 Videos

  • TRIGNOMETRIC RATIOS & IDENTITIES

    MOTION|Exercise Exercise -2(Level -II)|12 Videos

  • TRIGNOMETRIC RATIOS & IDENTITIES

    MOTION|Exercise Exercise -4(Level -II)|9 Videos

  • THREE DIMENSIONAL GEOMETRY (3 -D)

    MOTION|Exercise SOLVED EXAMPLE|33 Videos

  • TRIGONOMETRIC EQUATION

    MOTION|Exercise EXERCISE 4|10 Videos

Similar Questions

Explore conceptually related problems

If A+B+C=(3 pi)/(2), then cos2A+cos2B+cos2C is equal to (A)1-4cos A cos B cos C(B)4sin A sin B sin C(C)1+42cos A cos B cos C(D)1-4sin A sin B sin C

If A+B+C=(3 pi)/(2), then cos2A+cos2B+cos2C is equal to (i) 1-4cos A cos B cos C( is 4sin A sin B sin C (iii) 1+2cos A cos B cos C(iv)1-4sin A sin B sin C

If sin A + sin B + sin C = 3, then cos A + cos B + cos C is equal to

If A+B+C=(3 pi)/(2), then cos2A+cos2B+cos2C is equal to a.1-4cos A cos B cos C b.4sin A sin B sin C c.1+2cos A cos B cos Cd.1-4sin A sin B sin C

cos2B + cos2A-cos2C = 1-4sin A sin B cos C

Prove that a cos A+b cos B+c cos C=4R sin A sin B sin C

a cos A + b cos B + c cos C = 2a sin B sin C

a.cos A + b.cos B + c.cos C = 2a sin B sin C

If : A+B+C=pi, "then" : sin 2A + sin 2 B - sin 2 C= A) 4 sin A * cos B * cos C B) 4 sin B * sin C * cos A C) 4 sin C * cos A * cos B D) 4 sin A * sin B * sin C

MOTION-TRIGNOMETRIC RATIOS & IDENTITIES -Exercise 1
  1. The value of (sin 24^@ cos 6^@-sin 6^@sin 66^@)/(sin 21^@ cos 39^@-cos...

    Text Solution

    |

  2. The valud of sin 12^(@) sin 48^(@) sin 54^(@) is equal to-

    Text Solution

    |

  3. If A + B + C = (3pi)/2, then cos 2A + cos 2B + cos 2C is equal to (A) ...

    Text Solution

    |

  4. The expression (cos 6x+6cos 4x+15 cos 2x+10)/(cos 5x+5 cos 3x+10 co...

    Text Solution

    |

  5. The value of cos10^(@)-sin 10^(@) is

    Text Solution

    |

  6. If 0 lt x lt pi and cos x + sin x = 1/2, then tan x is

    Text Solution

    |

  7. If A lies in the third quadrant and 3 tan A-4 = 0, then 5 sin 2A + 3si...

    Text Solution

    |

  8. For -pi/2 lt theta lt pi/2 ,(sin theta + sin 2 theta)/(1+cos theta + c...

    Text Solution

    |

  9. Find the value of cos 12^(@)+cos 84^(@)+cos 156^(@)+cos 132^(@)

    Text Solution

    |

  10. Prove that cos 36^(@) cos 72^(@) cos 108^(@) cos 144^(@)=1//16.

    Text Solution

    |

  11. The value oif the expressin (1+cospi/10)(1+cos(3pi)/10)(1+cos(7pi)/10)...

    Text Solution

    |

  12. (cos 20^(@)+8 sin 70^(@) sin 50^(@) sin 10^(@))/( sin^(2)80^(@)) is eq...

    Text Solution

    |

  13. Which of the following is least ?

    Text Solution

    |

  14. Find the value of x for which f(x)=sqrt(sinx-cosx) is defined, x in [0...

    Text Solution

    |

  15. Find the number of solutions of sinx=x/(10)

    Text Solution

    |

  16. Number of solution of equation sin x = x^2 + x + 1 is

    Text Solution

    |

  17. Prove that the least positive value of x , satisfying tanx=x+1, lies i...

    Text Solution

    |

  18. If a sin^(2) x +b lies in the interval [-2,8] for every x in R then...

    Text Solution

    |

  19. Find the greatest value of c such that system of equation x^(2) + y^(...

    Text Solution

    |

  20. Given that sum(k=1)^35 sin5k^@ = tan(m/n)^@ , where m and n are relat...

    Text Solution

    |