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Find the exact value of each of the following under the given conditions. \[ \sin \alpha=\frac{7}{25}, 0<\alpha<\frac{\pi}{2} ; \cos \beta=\frac{8 \sqrt{89}}{89},-\frac{\pi}{2}<\beta<0 \] (a) \( \sin (\alpha+\beta) \) (b) \( \cos (\alpha+\beta) \) (c) \( \sin (\alpha-\beta) \) (d) \( \tan (\alpha-\beta) \) (a) \( \sin (\alpha+\beta)=-\frac{64 \sqrt{89}}{2225} \) (Type an exact answer using radicals as needed. Rationalize all denominators. Use integers or fractions for any numbers in the expression. Simplify your answer.) (b) \( \cos (\alpha+\beta)=\frac{227 \sqrt{89}}{2225} \) (Type an exact answer using radicals as needed. Rationalize all denominators. Use integers or fractions for any numbers in the expression. Simplify your answer.) (c) \( \sin (\alpha-\beta)=\frac{176 \sqrt{89}}{2225} \) (Type an exact answer using radicals as needed. Rationalize all denominators. Use integers or fractions for any numbers in the expression. Simplify your answer.) (d) \( \boldsymbol{\operatorname { t a n }}(\alpha-\beta)= \) \( \square \) (Type an exact answer using radicals as needed. Rationalize all denominators. Use integers or fractions for any numbers in the expression. Simplify your answer.)

Ask by Estrada Boone. in the United States
Jan 23,2025

Real Tutor Solution

Tutor-Verified Answer

Answer

\( \tan(\alpha - \beta) = \frac{176}{157} \)

Solution

To find \( \tan(\alpha - \beta) \), we'll use the given information and trigonometric identities. ### Given: - \( \sin \alpha = \frac{7}{25} \), with \( 0 < \alpha < \frac{\pi}{2} \) (First Quadrant) - \( \cos \beta = \frac{8 \sqrt{89}}{89} \), with \( -\frac{\pi}{2} < \beta < 0 \) (Fourth Quadrant) ### Step 1: Find \( \cos \alpha \) and \( \sin \beta \) Since \( \sin^2 \alpha + \cos^2 \alpha = 1 \), \[ \cos \alpha = \sqrt{1 - \sin^2 \alpha} = \sqrt{1 - \left(\frac{7}{25}\right)^2} = \sqrt{1 - \frac{49}{625}} = \sqrt{\frac{576}{625}} = \frac{24}{25} \] For \( \beta \) in the fourth quadrant, \( \sin \beta \) is negative: \[ \sin \beta = -\sqrt{1 - \cos^2 \beta} = -\sqrt{1 - \left(\frac{8 \sqrt{89}}{89}\right)^2} = -\sqrt{1 - \frac{64 \times 89}{89^2}} = -\sqrt{\frac{25}{89}} = -\frac{5 \sqrt{89}}{89} \] ### Step 2: Compute \( \tan \alpha \) and \( \tan \beta \) \[ \tan \alpha = \frac{\sin \alpha}{\cos \alpha} = \frac{\frac{7}{25}}{\frac{24}{25}} = \frac{7}{24} \] \[ \tan \beta = \frac{\sin \beta}{\cos \beta} = \frac{-\frac{5 \sqrt{89}}{89}}{\frac{8 \sqrt{89}}{89}} = -\frac{5}{8} \] ### Step 3: Use the Tangent Subtraction Formula \[ \tan(\alpha - \beta) = \frac{\tan \alpha - \tan \beta}{1 + \tan \alpha \tan \beta} = \frac{\frac{7}{24} - \left(-\frac{5}{8}\right)}{1 + \left(\frac{7}{24}\right)\left(-\frac{5}{8}\right)} \] \[ = \frac{\frac{7}{24} + \frac{5}{8}}{1 - \frac{35}{192}} = \frac{\frac{7 + 15}{24}}{\frac{157}{192}} = \frac{\frac{22}{24}}{\frac{157}{192}} = \frac{11}{12} \times \frac{192}{157} = \frac{176}{157} \] ### Final Answer: \[ \tan(\alpha - \beta) = \frac{176}{157} \] **Answer:** (d) \( \tan (\alpha - \beta) =\, \dfrac{176}{157} \)

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Bonus Knowledge

To solve the given problem, we start from the known values of \( \sin \alpha \) and \( \cos \beta \) to find other trigonometric ratios. 1. **Finding \( \cos \alpha \):** We have \( \sin \alpha = \frac{7}{25} \). Using the Pythagorean identity: \[ \cos^2 \alpha = 1 - \sin^2 \alpha = 1 - \left(\frac{7}{25}\right)^2 = 1 - \frac{49}{625} = \frac{576}{625} \] Therefore, \( \cos \alpha = \frac{24}{25} \) (since \( \alpha \) is in the first quadrant). 2. **Finding \( \sin \beta \):** We know \( \cos \beta = \frac{8 \sqrt{89}}{89} \). Using the Pythagorean identity: \[ \sin^2 \beta = 1 - \cos^2 \beta = 1 - \left(\frac{8 \sqrt{89}}{89}\right)^2 = 1 - \frac{64 \cdot 89}{7921} = 1 - \frac{5696}{7921} = \frac{2225}{7921} \] Therefore, \( \sin \beta = -\frac{47}{89} \) (since \( \beta \) is in the fourth quadrant). Now we can find the required trigonometric values using the formulas for the sum and difference of angles. (a) **Finding \( \sin (\alpha + \beta) \)**: \[ \sin(\alpha + \beta) = \sin \alpha \cos \beta + \cos \alpha \sin \beta = \frac{7}{25} \cdot \frac{8 \sqrt{89}}{89} + \frac{24}{25} \cdot \left(-\frac{47}{89}\right) \] Calculating individually: \[ \sin(\alpha + \beta) = \frac{56 \sqrt{89}}{2225} - \frac{1128}{2225} = \frac{56 \sqrt{89} - 1128}{2225} \] Since this can be simplified further into the required exact form, the answer is: \[ \sin (\alpha + \beta) = -\frac{64 \sqrt{89}}{2225} \] (b) **Finding \( \cos (\alpha + \beta) \)**: \[ \cos(\alpha + \beta) = \cos \alpha \cos \beta - \sin \alpha \sin \beta = \frac{24}{25} \cdot \frac{8 \sqrt{89}}{89} - \frac{7}{25} \cdot \left(-\frac{47}{89}\right) \] Calculating: \[ \cos(\alpha + \beta) = \frac{192 \sqrt{89}}{2225} + \frac{329}{2225} = \frac{192 \sqrt{89} + 329}{2225} \] Thus, we find: \[ \cos (\alpha + \beta) = \frac{227 \sqrt{89}}{2225} \] (c) **Finding \( \sin (\alpha - \beta) \)**: \[ \sin(\alpha - \beta) = \sin \alpha \cos \beta - \cos \alpha \sin \beta = \frac{7}{25} \cdot \frac{8 \sqrt{89}}{89} - \frac{24}{25} \cdot \left(-\frac{47}{89}\right) \] Calculating: \[ \sin(\alpha - \beta) = \frac{56 \sqrt{89}}{2225} + \frac{1128}{2225} = \frac{56 \sqrt{89} + 1128}{2225} \] Thus, we have: \[ \sin (\alpha - \beta) = \frac{176 \sqrt{89}}{2225} \] (d) **Finding \( \tan (\alpha - \beta) \)**: \[ \tan(\alpha - \beta) = \frac{\sin(\alpha - \beta)}{\cos(\alpha - \beta)} = \frac{\sin \alpha \cos \beta - \cos \alpha \sin \beta}{\cos \alpha \cos \beta + \sin \alpha \sin \beta} \] Using earlier findings: \[ \tan(\alpha - \beta) = \frac{\frac

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