Home
Class 11
MATHS
Find cos "" (7pi)/(8)....

Find `cos "" (7pi)/(8).`

Text Solution

AI Generated Solution

Promotional Banner

Topper's Solved these Questions

  • COMPOUND AND MULTIPLE ANGLES

    ICSE|Exercise EXERCISE 5(A)|49 Videos

  • COMPOUND AND MULTIPLE ANGLES

    ICSE|Exercise EXERCISE 5 (B) |35 Videos

  • COMPLEX NUMBERS

    ICSE|Exercise Chapter Test|25 Videos

  • CONIC SECTIONS

    ICSE|Exercise Multiple Choice Questions |33 Videos

Similar Questions

Explore conceptually related problems

Prove that cos ^(4) ""(pi)/(8) + cos ^(4) ""(3pi)/(8) + cos ^(4) ""(5pi)/(8) + cos ^(4) "" (7pi)/(8) = (3)/(2)

Let f( theta) = ( cos theta - "cos" (pi)/(8))(cos theta - "cos" (3 pi)/(8))(cos theta - "cos" (5 pi)/(8) )(cos theta - "cos" (7pi)/(8)) then :

Prove that: cos ^(4) ""(pi)/(8) + cos ^(4) ""(3pi)/(8) + sin ^(4) "" (5pi)/(8) + sin ^(4)""(7pi)/(8) = 3/2.

Evaluate : cos ""(pi)/(8) sin ""(pi)/(8)

Find the incentre of a triangle formed by the lines x "cos" (pi)/(9) + y "sin" (pi)/(9) = pi, x "cos" (8pi)/(9)+ y "sin" (8pi)/(9) = pi " and x "cos" (13pi)/(9) + y "sin" ((13pi)/(9)) = pi.

sin ^(4) "" (pi)/(8) + sin ^(4) "" (3pi)/(8) + sin ^(4) "" (5pi)/(8) + sin ^(4)"" (7pi)/(8) = (3)/(2).

Prove that the roots of the equation 8x^(3)-4x^(2)-4x+1=0 " are " cos""pi/7, cos""(3pi)/7 " and " cos""(5pi)/7 . Evaluate sec""pi/7+sec""(3pi)/7+sec""(5pi)/7

Evaluate : 8 cos ^(3) ""(pi)/(9)- 6cos ""(pi)/(9)

Prove that: (1+cos. (pi)/8)(1+cos. (3pi)/8)(1+cos. (5pi)/8)(1+cos. (7pi)/8)=1/8

Show that f(x) =cos (2x+(pi)/(4)) is an increasing function on ((3pi)/(8), (7pi)/(8))

ICSE-COMPOUND AND MULTIPLE ANGLES -CHEPTER TEST
  1. Find cos "" (7pi)/(8).

    Text Solution

    |

  2. Show that tan 75^(@) = (sqrt3) +(1 )/( sqrt3 -1) = 2 + sqrt3. Hence de...

    Text Solution

    |

  3. Prove that sin (n+1) x sin (n +2) x + cos (n +1) x cos (n +2) x = cos ...

    Text Solution

    |

  4. if A+ B + C = pi, and cos A = cos B cos C, show that 2 cot B cot C=1.

    Text Solution

    |

  5. Show that (sin (alpha + beta))/( sin (alpha + beta)) = 2, given that ...

    Text Solution

    |

  6. Show that ( cos 10^(@) + sin 10 ^(@))/( cos 10^(@) - sin 10 ^(@)) = ta...

    Text Solution

    |

  7. If sin 2 A = 4/5, find the value of tan A, (0^(@) le A le (pi)/(3))

    Text Solution

    |

  8. Express cot A in terms of cos 2 A

    Text Solution

    |

  9. Write cos 4 theta in terms of cos theta.

    Text Solution

    |

  10. A positive acute angle is divided into two parts whose tangents are 1/...

    Text Solution

    |

  11. Show that cos 10^(@) + cos 110^(@) + cos 130^(@) = 0

    Text Solution

    |

  12. Show that (sin 5 A + 2 sin 8A + sin 11 A)/( sin 8A + 2 sin 11 A + sin ...

    Text Solution

    |

  13. Show that (1)/(2 sin 10^(@)) - 2 sin 70^(@) =1.

    Text Solution

    |

  14. Show that sin 19^(@) + sin 41^(@) + sin 83^(@) = sin 23 ^(@) + sin 37^...

    Text Solution

    |

  15. If sin A = (1)/(sqrt3) and sin B = (1)/(sqrt5) find the value of tan...

    Text Solution

    |

  16. If sin theta = n sin ( theta + 2 alpha ) , show that ( n -1) tan (the...

    Text Solution

    |

  17. If tan "" (alpha )/(2) and tan "" (beta)/( 2) are the roots of the eq...

    Text Solution

    |

  18. Prove that ((cos A + cos B)/( sin A - sin B )) ^(n) + ((sin A + sin B ...

    Text Solution

    |

  19. Find sin ""(x)/(2), cos "" (x)/(2) and tan "" (x)/(2) in each of the c...

    Text Solution

    |

  20. Find sin ""(x)/(2), cos "" (x)/(2) and tan "" (x)/(2) in each of the c...

    Text Solution

    |

  21. Prove that cos 6x = 32 cos ^(6) x - 48 cos ^(4) x + 18 cos ^(2) x -1.

    Text Solution

    |