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Find the magnitude of angle A, if : si...

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

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To solve the equation \( \sin^2(2x) + \sin^2(60^\circ) = 1 \), we will follow these steps: ### Step 1: Substitute the value of \( \sin(60^\circ) \) We know that: \[ \sin(60^\circ) = \frac{\sqrt{3}}{2} \] Thus, we can calculate \( \sin^2(60^\circ) \): \[ \sin^2(60^\circ) = \left(\frac{\sqrt{3}}{2}\right)^2 = \frac{3}{4} \] ### Step 2: Rewrite the equation Now, substitute \( \sin^2(60^\circ) \) into the original equation: \[ \sin^2(2x) + \frac{3}{4} = 1 \] ### Step 3: Isolate \( \sin^2(2x) \) To isolate \( \sin^2(2x) \), subtract \( \frac{3}{4} \) from both sides: \[ \sin^2(2x) = 1 - \frac{3}{4} \] \[ \sin^2(2x) = \frac{1}{4} \] ### Step 4: Take the square root Now, take the square root of both sides: \[ \sin(2x) = \pm \frac{1}{2} \] ### Step 5: Find the angles for \( \sin(2x) = \frac{1}{2} \) The angles for which \( \sin(\theta) = \frac{1}{2} \) are: \[ 2x = 30^\circ + n \cdot 360^\circ \quad \text{or} \quad 2x = 150^\circ + n \cdot 360^\circ \quad (n \in \mathbb{Z}) \] ### Step 6: Solve for \( x \) Dividing by 2, we get: 1. \( x = 15^\circ + n \cdot 180^\circ \) 2. \( x = 75^\circ + n \cdot 180^\circ \) ### Step 7: Consider the principal value For the principal value, we can take \( n = 0 \): - From the first equation: \( x = 15^\circ \) - From the second equation: \( x = 75^\circ \) ### Conclusion The possible values for \( x \) are \( 15^\circ \) and \( 75^\circ \).
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ICSE-TRIGONOMETRICAL RATIOS OF STANDARD ANGLES-EXERCISE 23(C)
  1. Find the magnitude of angle A, if : sin^(2)2x+sin^(2)60^(@)=1

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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