Home
Class 11
MATHS
Prove that 4cos(2pi)/7dotcospi/7-1=2cos(...

Prove that `4cos(2pi)/7dotcospi/7-1=2cos(2pi)/7dot`

Promotional Banner

Topper's Solved these Questions

  • STRAIGHT LINES

    CENGAGE PUBLICATION|Exercise All Questions|486 Videos

Similar Questions

Explore conceptually related problems

Prove that cos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)=-1/2

Prove that cos((2pi)/(15))cos((4pi)/(15))cos((8pi)/(15))cos((16pi)/(15))=1/(16)

cos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)

Prove that, cos(pi/5)-cos((2pi)/5)=1/2

Prove that "cos" (2pi)/15 cdot "cos"(4pi)/15 cdot "cos" (8pi)/15 "cos"(14pi)/15=1/(16)

Show that cos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)=-1/2

Prove that, "cos" pi/11 "cos" (2pi)/11 "cos" (3pi)/11 "cos" (4pi)/11 "cos" (5pi)/11 = 1/32

Prove that cos^8(pi/8)+cos^8((3pi)/8)+cos^8((5pi)/8)+cos^8((7pi)/8)=17/16

"cos"(2pi)/(7) +"cos"(4pi)/(7)+"cos"(6pi)/(7)

Prove that cos^2( pi/8)+cos^2((3pi)/8)+cos^2 ((5pi)/8)+cos^2 ((7pi)/8)=2.

CENGAGE PUBLICATION-TRIGONOMETRIC FUNCTIONS-All Questions
  1. Show that sin^2 5^0+sin^2 10^0+sin^2 15^0+....+sin^2 90^0=9 1/2dot

    Text Solution

    |

  2. Solve (sin^3x/2-cos^3x/2)/(2+sinx)=(cosx)/3

    Text Solution

    |

  3. Prove that 4cos(2pi)/7dotcospi/7-1=2cos(2pi)/7dot

    Text Solution

    |

  4. Suppose alpha,beta,gammaa n ddelta are the interior angles of regular ...

    Text Solution

    |

  5. Find the value of cos^2pi/(16)+cos^2(3pi)/(16)+cos^2(5pi)/(16)+cos^2(7...

    Text Solution

    |

  6. Solve (sqrt(5)-1)/(sinx)+(sqrt(10+2sqrt(5)))/(cosx)=8,x in (0,pi/2)

    Text Solution

    |

  7. Prove that cos((2pi)/(15))cos((4pi)/(15))cos((8pi)/(15))cos((16pi)/(15...

    Text Solution

    |

  8. Let L be the line of intersection of the planes 2x""+""3y""+""z""=""...

    Text Solution

    |

  9. If sin(120° – α) = sin(120° – β) and 0 < α, β < π then find the relati...

    Text Solution

    |

  10. Solve cosxcos2xcos3x=1/4

    Text Solution

    |

  11. Prove that sin 6^@ sin 42^@sin 66^@sin 78^@=1/16

    Text Solution

    |

  12. If the since of the angles A and B of a triangle ABCsatisfy the equati...

    Text Solution

    |

  13. Find the sign of the values of tan113^0-cos107^0=a and tan107^0-cos105...

    Text Solution

    |

  14. Solve the equation (sqrt(3))/2sinx-cosx=cos^2x

    Text Solution

    |

  15. Each question contains statements given in two columns which have to b...

    Text Solution

    |

  16. If xsina+ysin2a+zsin3a=sin4a, xsinb+ysin2b+zsin3b=sin4b, xsinc+ysin2...

    Text Solution

    |

  17. Prove that (sinx-cosx+1)/(sinx+cosx-1)=secx+tanx

    Text Solution

    |

  18. The lengths of the medians through acute angles of a right-angled tr...

    Text Solution

    |

  19. If 2tan^2x-5secx=1 is satisfied by exactly seven distinct values of x ...

    Text Solution

    |

  20. In a triangle tanA+tanB+tanC=6 and tanAtanB=2, then the values of tanA...

    Text Solution

    |