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Solve the following equations for A, if ...

Solve the following equations for A, if :
(i) `sin 3 A = (sqrt(3))/(2)`
(ii) `sqrt(3) cot 2A = 1`

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The correct Answer is:
To solve the equations for \( A \), we will tackle each equation step by step. ### (i) Solve \( \sin 3A = \frac{\sqrt{3}}{2} \) **Step 1:** Recognize the value of sine. We know that \( \sin 60^\circ = \frac{\sqrt{3}}{2} \). **Hint:** Recall the unit circle values for sine at common angles. **Step 2:** Set the angles equal. Since \( \sin 3A = \sin 60^\circ \), we can set the angles equal to each other: \[ 3A = 60^\circ + n \cdot 360^\circ \quad \text{or} \quad 3A = 180^\circ - 60^\circ + n \cdot 360^\circ \] where \( n \) is any integer. **Hint:** Use the property of sine that states \( \sin x = \sin(180^\circ - x) \). **Step 3:** Solve for \( A \). From \( 3A = 60^\circ \): \[ A = \frac{60^\circ}{3} = 20^\circ \] From \( 3A = 120^\circ \): \[ A = \frac{120^\circ}{3} = 40^\circ \] **Hint:** Divide by 3 to isolate \( A \). **Step 4:** General solution. The general solutions for \( A \) can be expressed as: \[ A = 20^\circ + n \cdot 120^\circ \quad \text{and} \quad A = 40^\circ + n \cdot 120^\circ \] for any integer \( n \). ### (ii) Solve \( \sqrt{3} \cot 2A = 1 \) **Step 1:** Rearrange the equation. We can rewrite the equation as: \[ \cot 2A = \frac{1}{\sqrt{3}} \] **Hint:** Remember that \( \cot \theta = \frac{1}{\tan \theta} \). **Step 2:** Identify the angle. We know that \( \cot 60^\circ = \frac{1}{\sqrt{3}} \). **Hint:** Recall the values of cotangent at common angles. **Step 3:** Set the angles equal. Thus, we have: \[ 2A = 60^\circ + n \cdot 360^\circ \quad \text{or} \quad 2A = 180^\circ - 60^\circ + n \cdot 360^\circ \] **Step 4:** Solve for \( A \). From \( 2A = 60^\circ \): \[ A = \frac{60^\circ}{2} = 30^\circ \] From \( 2A = 120^\circ \): \[ A = \frac{120^\circ}{2} = 60^\circ \] **Hint:** Divide by 2 to isolate \( A \). **Step 5:** General solution. The general solutions for \( A \) can be expressed as: \[ A = 30^\circ + n \cdot 180^\circ \quad \text{and} \quad A = 60^\circ + n \cdot 180^\circ \] for any integer \( n \). ### Summary of Solutions From the first equation, we found: - \( A = 20^\circ \) or \( A = 40^\circ \) From the second equation, we found: - \( A = 30^\circ \) or \( A = 60^\circ \)
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