Home
Class 9
MATHS
Find the magnitude of angle A, if : 2s...

Find the magnitude of angle A, if :
`2sin^(2)A-3sinA+1=0`

Text Solution

AI Generated Solution

The correct Answer is:
To find the magnitude of angle A from the equation \(2\sin^2 A - 3\sin A + 1 = 0\), we can follow these steps: ### Step 1: Rewrite the equation The given equation is a quadratic in terms of \(\sin A\). We can rewrite it as: \[ 2\sin^2 A - 3\sin A + 1 = 0 \] ### Step 2: Identify coefficients In the quadratic equation \(ax^2 + bx + c = 0\), we identify: - \(a = 2\) - \(b = -3\) - \(c = 1\) ### Step 3: Factor the quadratic To factor the quadratic, we can look for two numbers that multiply to \(ac = 2 \cdot 1 = 2\) and add up to \(b = -3\). The numbers are \(-2\) and \(-1\). Thus, we can rewrite the equation: \[ 2\sin^2 A - 2\sin A - \sin A + 1 = 0 \] Now, we can factor by grouping: \[ 2\sin A(\sin A - 1) - 1(\sin A - 1) = 0 \] This can be factored as: \[ (2\sin A - 1)(\sin A - 1) = 0 \] ### Step 4: Set each factor to zero Now, we set each factor equal to zero: 1. \(2\sin A - 1 = 0\) 2. \(\sin A - 1 = 0\) ### Step 5: Solve for \(\sin A\) From the first equation: \[ 2\sin A = 1 \implies \sin A = \frac{1}{2} \] From the second equation: \[ \sin A = 1 \] ### Step 6: Find the angles Now we find the angles corresponding to these sine values: 1. \(\sin A = \frac{1}{2}\) occurs at \(A = 30^\circ\) (and also \(A = 150^\circ\) in the range of \(0^\circ\) to \(360^\circ\)). 2. \(\sin A = 1\) occurs at \(A = 90^\circ\). ### Step 7: List all possible angles Therefore, the possible values for angle \(A\) are: - \(A = 30^\circ\) - \(A = 90^\circ\) - (and \(A = 150^\circ\) if considering angles beyond the first quadrant). ### Final Answer The magnitudes of angle \(A\) are \(30^\circ\), \(90^\circ\), and \(150^\circ\). ---
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRICAL RATIOS OF STANDARD ANGLES

    ICSE|Exercise EXERCISE 23(A)|68 Videos
  • TRIGONOMETRICAL RATIOS OF STANDARD ANGLES

    ICSE|Exercise EXERCISE 23(B)|34 Videos
  • TRIGONOMETRICAL RATIOS

    ICSE|Exercise EXERCISE 22(B)|50 Videos
  • TRIGONOMETRY

    ICSE|Exercise TOPIC -4 ( COMPLEMENTARY ANGLES ) (4 MARKS QUESTIONS )|4 Videos

Similar Questions

Explore conceptually related problems

Find the magnitude of angle A, if : 2cos^(2)A-3cosA+1=0

Find the magnitude of angle A, if : sin^(2)2A+sin^(2)60^(@)=1

Find the magnitude of angle A, if : 2sinAcosA-cosA-2sinA+1=0

Find the magnitude of angle A, if : 2sinAcosA-cosA-2sinA+1=0

Find the magnitude of angle A, if : 4sinAsin2A+1-2sin2A=2sinA

Find the magnitude of angle A, if : sin^(2)2x+sin^(2)60^(@)=1

Find the magnitude of angle A, if : (i) 2 cos^(2)A - 3 cos A + 1 = 0 (ii) 2 tan 3A cos 3A - tan 3A + 1 = 2 cos 3A

Find the value of angle A , if : 2 sin A=1

Find the magnitude of angle A, if : 3cot^(2)(A-5^(@))=1

Find the magnitude of angle A, if : 3cot^(2)(A-5^(@))=1

ICSE-TRIGONOMETRICAL RATIOS OF STANDARD ANGLES-EXERCISE 23(C)
  1. Find the magnitude of angle A, if : 2sin^(2)A-3sinA+1=0

    Text Solution

    |

  2. Solve the following equations for A, if : 2sinA=1

    Text Solution

    |

  3. Solve the following equations for A, if : 2cos2A=1

    Text Solution

    |

  4. Solve the following equations for A, if : sin3A=sqrt(3)/2

    Text Solution

    |

  5. Solve the following equations for A, if : sec2A=2

    Text Solution

    |

  6. Solve the following equations for A, if : sqrt(3)tanA=1

    Text Solution

    |

  7. Solve the following equations for A, if : tan3A=1

    Text Solution

    |

  8. Solve the following equations for A, if : 2sin3A=1

    Text Solution

    |

  9. Solve the following equations for A, if : sqrt(3)cot2A=1

    Text Solution

    |

  10. Calculate the value of A, if : (sinA-1)(2cosA-1)=0

    Text Solution

    |

  11. Calculate the value of A, if : (tanA-1)(cosec3A-1)=0

    Text Solution

    |

  12. Calculate the value of A, if : (sec2A-1)(cosec3A-1)=0

    Text Solution

    |

  13. Calculate the value of A, if : cos3A.(2sin2A-1)=0

    Text Solution

    |

  14. Calculate the value of A, if : (cosec2A-2)(cot3A-1)=0

    Text Solution

    |

  15. If 2sinx^(@)-1=0 and x^(@) is an acute angle, find: (i) bsinx^(@)" ...

    Text Solution

    |

  16. If 4cos^(2)x^(@)-1=0 and 0 le x^(@) le 90^(@), find : x^(@)

    Text Solution

    |

  17. If 4cos^(2)x^(@)-1=0 and 0 le x^(@) le 90^(@), find : sin^(2)x^(@)+c...

    Text Solution

    |

  18. If 4cos^(2)x^(@)-1=0 and 0 le x^(@) le 90^(@), find : 1/(cos^(2)x^(@...

    Text Solution

    |

  19. If 4sin^(2)theta-1=0 and angle theta is less than 90^(@), find the val...

    Text Solution

    |

  20. If sin3A=1 and 0 le A le 90^(@), find : sin A

    Text Solution

    |

  21. If sin3A=1 and 0 le A le 90^(@), find : cos 2A

    Text Solution

    |