Home
Class 11
MATHS
Statement-I If alpha=(pi)/(18) then cos ...

Statement-I If `alpha=(pi)/(18)` then `cos alpha+ cos 2 alpha+..... +cos18 alpha=0`
Statement- II If `(a+2) sin theta(2a-1) cos theta=2a+1` then `tan theta=(4)/(3)`
Which of the above statements is correct

A

Only I

B

Only II

C

Btoh I & II

D

Neither I nor II

Text Solution

Verified by Experts

The correct Answer is:
B
Promotional Banner

Topper's Solved these Questions

  • REVISION EXERCISE

    AAKASH SERIES|Exercise COMPOUND ANGLES|12 Videos

  • REVISION EXERCISE

    AAKASH SERIES|Exercise MULTIPLE & SUB MULTIPLE ANGLES|20 Videos

  • REAL FUNCTIONS

    AAKASH SERIES|Exercise EXERCISE-1|34 Videos

  • STRAIGHT LINES

    AAKASH SERIES|Exercise ADDITIONAL PRACTICE EXERCISE (LEVEL-II (ADVANCED) PRACTICE SHEET (ADDVANCED)) (Comprehension Type Questions)|6 Videos

Similar Questions

Explore conceptually related problems

If sin ( theta + alpha ) = cos ( theta + alpha ) , then tan theta =

Statement I : If m cos(theta+alpha)=n cos (theta-alpha) then tan theta.tan alpha=(m+n)/(m-n) Statement II : If (sin(alpha+beta))/(sin(alpha-beta))=(a+b)/(a-b) then tan alpha.cot beta=(a)/(b) Which of the above statements is correct ?

Statement-I: If mcos(theta + alpha) =ncos(theta-alpha) then tan alpha tan theta =(m+n)/(m-n) Statement:II If (sin(alpha + beta))/(sin(alpha-beta)) =(a+b)/(a-b) , then tan alpha cot beta =a/b Which of the above statements is correct?

(sin 5 alpha-sin3alpha)/(cos 5 alpha+2 cos 4 alpha+cos 3alpha)=

I : If (cos alpha )/(a)=(sin alpha )/(b) then a cos 2 alpha + b cos 2 alpha =a II : If (sin alpha )/(a) =(cos alpha )/(b) then a sin 2 alpha + b cos 2 alpha = a

If 2 cos theta+2 cos 3 theta=cos alpha and 2 sin theta+2 sin 3 theta=sin alpha then show that cos 2 theta=-7/8

If cos theta = cos alpha cos beta, "then tan" (theta - alpha)/(2) is equal to

If ( cos 2 alpha+ isin 2alpha)(cos 2 beta+ isin 2 beta)= cos theta+isin theta , then find the value of theta .

Statement I : Minimum value of (3 sn theta -4 cos theta ) ( 3 cos theta + 4 sin theta ) is -(25)/(2) Statement II : Minimum value of 9 tan^(2) x+ 16 cot^(2) x is 24 Which of the above statement is correct ?

AAKASH SERIES-REVISION EXERCISE-PROPERTIES OF TRIANGLES
  1. Statement-I If alpha=(pi)/(18) then cos alpha+ cos 2 alpha+..... +cos1...

    Text Solution

    |

  2. In a triangle ABC, if A,B, C are in A.P and b:c =sqrt3:sqrt2, then

    Text Solution

    |

  3. In Delta ABC, if B=60^@,C=45^@ and D divides BC internally in the rati...

    Text Solution

    |

  4. If a=4,b=5,c=6 then

    Text Solution

    |

  5. In DeltaABC, if a= 2, b= sqrt(6) and c= sqrt(3)+1 then A=

    Text Solution

    |

  6. In DeltaABC, if the sides a,b,c are the roots of x^(3)-11x^(2)+38x-40=...

    Text Solution

    |

  7. In triangle ABC, triangle A^(1)B^(1)C^(1) are such that B=B^(1),A+A^(1...

    Text Solution

    |

  8. In triangle ABC, right angle at B if s-a=3, s-c=2 then a,c are

    Text Solution

    |

  9. The distance of the orthocentre from the vertices A,B,C are in the rat...

    Text Solution

    |

  10. If H is the orthocentre of DeltaABC and AH=x, BH=y, CH=z then (abc)/(x...

    Text Solution

    |

  11. If the angles A,B,C of a triangle are in A.P and sides a,b,c are in G....

    Text Solution

    |

  12. In triangle ABC, range of (a^(2)+b^(2)+c^(2))/(ab+bc+ca) is (a,b,c are...

    Text Solution

    |

  13. In DeltaABC, if AD is the altitude and O is the orthocentre of DeltaAB...

    Text Solution

    |

  14. If R is the circumradius of equilateral traingle DeltaABC then circumr...

    Text Solution

    |

  15. If alpha, beta, gamma are lenghts of internal bisectors of angles A,B,...

    Text Solution

    |

  16. In DeltaABC, a=2b,|A-B|=(pi)/(3) then angle C=

    Text Solution

    |

  17. In Delta ABC , if x=tan((B-C)/(2))tan.(A)/(2),y=tan((C-A)/(2))tan.(B)/...

    Text Solution

    |

  18. In a triangle ABC, D and E are the mid-points of BC, CA respectively. ...

    Text Solution

    |

  19. The alternate vertices of a regular hexagon are joined to form another...

    Text Solution

    |

  20. In DeltaABC if r(1)=2r(1)=3r(3) and D is the mid point of BC then cos ...

    Text Solution

    |

  21. If (sin 3B)/(sinB)=((a^(2)-c^(2))/(2ac)) then a^(2),b^(2),c^(2) are in

    Text Solution

    |