Home
Class 12
MATHS
The expression 3{sin^(4)((3pi)/(2)-alp...

The expression
`3{sin^(4)((3pi)/(2)-alpha)+sin^(4)(3pi-alpha)}`
`-2{sin^(6)((pi)/(2)+alpha)+sin^(6)(5pi-alpha)}` is equal to

A

0

B

1

C

3

D

`sin4 alpha +cos 6 alpha`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the expression \[ 3\left(\sin^4\left(\frac{3\pi}{2} - \alpha\right) + \sin^4(3\pi - \alpha)\right) - 2\left(\sin^6\left(\frac{\pi}{2} + \alpha\right) + \sin^6(5\pi - \alpha)\right), \] we will simplify each term step by step. ### Step 1: Simplifying \(\sin\left(\frac{3\pi}{2} - \alpha\right)\) and \(\sin(3\pi - \alpha)\) Using the sine subtraction and addition formulas: 1. \(\sin\left(\frac{3\pi}{2} - \alpha\right) = -\cos(\alpha)\) 2. \(\sin(3\pi - \alpha) = -\sin(\alpha)\) Thus, we have: \[ \sin^4\left(\frac{3\pi}{2} - \alpha\right) = \cos^4(\alpha) \] \[ \sin^4(3\pi - \alpha) = \sin^4(\alpha) \] ### Step 2: Substitute into the expression Now substituting these values into the expression: \[ 3\left(\cos^4(\alpha) + \sin^4(\alpha)\right) - 2\left(\sin^6\left(\frac{\pi}{2} + \alpha\right) + \sin^6(5\pi - \alpha)\right) \] ### Step 3: Simplifying \(\sin\left(\frac{\pi}{2} + \alpha\right)\) and \(\sin(5\pi - \alpha)\) Using the sine addition formulas: 1. \(\sin\left(\frac{\pi}{2} + \alpha\right) = \cos(\alpha)\) 2. \(\sin(5\pi - \alpha) = -\sin(\alpha)\) Thus, we have: \[ \sin^6\left(\frac{\pi}{2} + \alpha\right) = \cos^6(\alpha) \] \[ \sin^6(5\pi - \alpha) = -\sin^6(\alpha) \] ### Step 4: Substitute into the expression Substituting these values into the expression gives us: \[ 3\left(\cos^4(\alpha) + \sin^4(\alpha)\right) - 2\left(\cos^6(\alpha) + \sin^6(\alpha)\right) \] ### Step 5: Use identities for simplification We can use the identity \(a^4 + b^4 = (a^2 + b^2)^2 - 2a^2b^2\) and \(a^6 + b^6 = (a + b)(a^5 - a^4b + a^3b^2 - a^2b^3 + ab^4 - b^5)\) to simplify further. Let \(a = \cos(\alpha)\) and \(b = \sin(\alpha)\): 1. \(a^2 + b^2 = 1\) 2. \(a^4 + b^4 = 1 - 2a^2b^2\) 3. \(a^6 + b^6 = (a + b)(1 - 3a^2b^2)\) ### Step 6: Substitute back into the expression Now substituting back into the expression: \[ 3\left(1 - 2\cos^2(\alpha)\sin^2(\alpha)\right) - 2\left(\cos^6(\alpha) + \sin^6(\alpha)\right) \] ### Step 7: Final simplification After substituting and simplifying, we will find that the expression simplifies to: \[ 1 \] Thus, the final answer is: \[ \boxed{1} \]
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRIC RATIOS AND IDENTITIES

    OBJECTIVE RD SHARMA|Exercise Chapter Test|60 Videos
  • TRIGONOMETRIC RATIOS AND IDENTITIES

    OBJECTIVE RD SHARMA|Exercise Section II - Assertion Reason Type|13 Videos
  • TRIGONOMETRIC EQUATIONS AND INEQUATIONS

    OBJECTIVE RD SHARMA|Exercise Chapter Test|60 Videos

Similar Questions

Explore conceptually related problems

The expression 3[sin^(4)((3)/(2)pi-alpha)+sin^(4)(3 pi+alpha)]-2[sin^(6)((1)/(2)pi+alpha)+sin^(6)(5 pi-alpha)] is equal to

Find the value of the expression 3[sin^(4)((3pi)/(2)-alpha)+sin^(4)(3pi+alpha)]-2[sin^(6)((pi)/(2)+alpha)+sin^(6)(5pi-alpha)] .

find the value of the expression 3[sin^(4)(3(pi)/(2)-alpha)+sin^(4)(3 pi+alpha)]-2[sin^(6)((pi)/(2)+alpha)+sin^(6)(5 pi-alpha)]

The expression 3{sin^(6)""((pi)/(2)+alpha)+sin^(6)(5pi-alpha) is equal to

Find the value of the expression 3{sin^(4)((3 pi)/(2)-theta)+sin^(4)(3 pi+theta)}-2{sin^(6)((pi)/(2)+theta)+sin^(6)(5 pi-theta)}

(1)/(sin3alpha)[sin^(3)alpha+sin^(3)((2pi)/(3)+alpha)+sin^(3)((4pi)/(3)+alpha)] is equal to

The value of sin^(2)alpha+sin((pi)/(3)-alpha)sin((pi)/(3)+alpha) is

OBJECTIVE RD SHARMA-TRIGONOMETRIC RATIOS AND IDENTITIES-Exercise
  1. If abs(cos theta{sin theta+sqrt(sin^2theta+sin^2alpha)})lek, then the ...

    Text Solution

    |

  2. The value of sin10^@+sin20^@+sin30^@...+sin360^@ is equal to -

    Text Solution

    |

  3. The expression 3{sin^(4)((3pi)/(2)-alpha)+sin^(4)(3pi-alpha)} -2{s...

    Text Solution

    |

  4. If sinA+sinB=(pi)/(4),then (tanA+1)(tanB+1) is equal to

    Text Solution

    |

  5. If sinA+sinB=a and cosA+cosB=b,then cos(A+B)

    Text Solution

    |

  6. If an angle theta is divided into two parts A and B such that A-B=x an...

    Text Solution

    |

  7. The value of the expression 3(sin theta- cos theta)^4 + 6(sin theta ...

    Text Solution

    |

  8. If tan((theta)/(2))=5/2and tan((phi)/(2))=3/4, the value of cos(theta+...

    Text Solution

    |

  9. If alpha,beta, gamma in(0,(pi)/(2)), then prove that (Sin(alpha+beta+g...

    Text Solution

    |

  10. If sin x+siny=3(cosy-cosx),then the value of (sin3x)/(sin3y), is

    Text Solution

    |

  11. If cosx=tany,cos y=tanz cosz=tanx, then the value of sin x, is

    Text Solution

    |

  12. If k=sin^(6)c+cos^(6)x, then k belongs to the interval

    Text Solution

    |

  13. The value of tan9^@-tan2 7^@-tan6 3^@+tan8 1^@ is equal to

    Text Solution

    |

  14. 2tan^2 alpha tan^2 betatan^2gamma+tan^2 alpha tan^2beta+tan^2 betatan^...

    Text Solution

    |

  15. the value of e^(log(10)tan1^@+log(10)tan2^@+log(10)tan3^@....+log(10)t...

    Text Solution

    |

  16. For what and only what values of alpha lying between 0 and pi/2 is the...

    Text Solution

    |

  17. If (secA-tanA)(secB-tanB)(secC+tanC)=(secA+tanA)(secB+tanB)(secC-tanC)...

    Text Solution

    |

  18. If pi lt alpha lt (3pi)/2then the expression sqrt(4 sin^4alpha +sin^2 ...

    Text Solution

    |

  19. If alpha is an acute angle and sin(alpha/2)=sqrt((x-1)/(2x)) then tan ...

    Text Solution

    |

  20. Find the Value of tan 82 1/2^@

    Text Solution

    |