Home
Class 11
MATHS
Prove that: "sin"20^0"sin"40^0"sin"60^0"...

Prove that: `"sin"20^0"sin"40^0"sin"60^0"sin"80^0=3/(16)`

Text Solution

AI Generated Solution

To prove that \( \sin 20^\circ \sin 40^\circ \sin 60^\circ \sin 80^\circ = \frac{3}{16} \), we can use some trigonometric identities and properties. ### Step-by-step Solution: 1. **Use the identity for sine of complementary angles**: We know that \( \sin(90^\circ - x) = \cos x \). Therefore, we can rewrite \( \sin 80^\circ \) as: \[ \sin 80^\circ = \cos 10^\circ ...
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRIC RATIOS OF COMPOUND ANGLES

    RD SHARMA|Exercise Solved Examples And Exercises|149 Videos

Similar Questions

Explore conceptually related problems

Prove that: sin20^(0)sin40^(0)sin60^(@)sin80^(@)=(3)/(16)

sin20^(0)sin40^(0)sin60^(0)sin80^(@)=(3)/(16)

Prove that: i) sin20^(@)sin40^(@)sin60^(@)sin80^(@)=3/16 ii) sin10^(@)sin50^(@)sin60^(@)sin70^(@)=sqrt(3)/16 iii) sin20^(@)sin40^(@)sin80^(@)=sqrt(3)/8

Prove that: sin10^(0)sin30^(0)sin50^(@)sin70^(@)=(1)/(16)

sin20^(@)sin40^(@)sin60^(@)sin80^(@)

sin20sin40sin80

sin 20^(@) sin 40^(@) sin 60^(@) sin 80^(@) =(3)/(16)

Prove that sin10+sin20+sin40+sin50=sin70+sin80

Prove that: sin50^(@)-sin70^(@)+sin10^(@)=0

RD SHARMA-TRIGONOMETRIC RATIOS OF MULTIPLE AND SUBMULTIPLE ANGLES-Solved Examples And Exercises
  1. Prove that : cos Acos(60-A)cos(60+A)=1/4cos3A

    Text Solution

    |

  2. Prove that: sin A sin(60-A)sin(60+A)=1/4sin3Adot

    Text Solution

    |

  3. Prove that: "sin"20^0"sin"40^0"sin"60^0"sin"80^0=3/(16)

    Text Solution

    |

  4. prove sin(5theta) = 16sin^5(theta)-20sin^3(theta)+5sin(theta)

    Text Solution

    |

  5. Prove the following identity: 4(cos^3 10^0+sin^3\ \ 20^0)=\ 3\ (cos 10...

    Text Solution

    |

  6. Prove the following identity: cos^3thetas in3theta+sin^3thetacos3theta...

    Text Solution

    |

  7. Prove the following identity: tan θ tan(60^@ +θ)tan(60^@ −θ)=]ta...

    Text Solution

    |

  8. Prove that: t a nA+tan(60^0+A)-t a n(60^0-A)=3t a n3ALet's use the sum...

    Text Solution

    |

  9. Prove that: cotA+"cot"(60^0+A)-cot(60^0-A)=3cot3A

    Text Solution

    |

  10. Prove the following identity: cot A+cot(60^0+A)+cot(120^0+A)=3cot3A

    Text Solution

    |

  11. Prove that: sin^3A+sin^3((2pi)/3+A)+sin^3((4pi)/3+A)=-3/4sin3Adot

    Text Solution

    |

  12. Maximum value of |costhetacos(60^0-theta)cos(60^0+theta) for all valu...

    Text Solution

    |

  13. Prove that: sin(pi/5)sin(2pi/5)sin(3pi/5)sin(4pi/5)=5/16

    Text Solution

    |

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

    Text Solution

    |

  15. Prove that: sin 12^0sin 48^0sin 54^0=1/8dot

    Text Solution

    |

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

    Text Solution

    |

  17. Prove that ; 4 sin 27^@=(5+sqrt(5))-sqrt((3-sqrt(5))) we have

    Text Solution

    |

  18. Prove that : sin^2(72^@) - sin^2 (60^@) = (sqrt5 - 1)/8

    Text Solution

    |

  19. Prove that: sin^2 24^0-sin^2 6^0=(sqrt(5)-1)/8

    Text Solution

    |

  20. Prove that: sin^2 42^0-cos^2 78^0=(sqrt(5)+1)/8

    Text Solution

    |