1. Convert the following into remaining two units of measurements of an angle: (a) 60°, (b) 3.67°, (c) (11/6) R. 2. Evaluate: (a) cot 75°, (b) tan(25π/2), (c) tan(π/8). 3. Prove th... 1. Convert the following into remaining two units of measurements of an angle: (a) 60°, (b) 3.67°, (c) (11/6) R. 2. Evaluate: (a) cot 75°, (b) tan(25π/2), (c) tan(π/8). 3. Prove that: sin(A+B)sin(A-B) = sin²A sin²B. 4. Show that: tan 56° = (cos 11° + sin 11°) / (cos 11° - sin 11°). 5. Prove that: (1 + sin θ - cos θ) / (1 + sin θ + cos θ) = tan(θ/2). 6. Prove that: √(1 - cos 2θ) / 2 = sin θ. 7. In ΔABC, prove that tan A + tan B + tan C = tan A tan B tan C. 8. Prove that: √(2 + √(2 + 2cos θ)) = -2 cos θ. 9. Evaluate: sin 10° sin 30° sin 50° sin 70°. 10. Draw the graph of 3 sin(πx/2) (-2π < x < 2π).
Understand the Problem
The question consists of several mathematical problems related to trigonometric functions, evaluations, and graphing, which seem to be part of an assignment on angles and their measurements.
Answer
1. (a) $\frac{\pi}{3} \text{ rad}$, (b) $204.25°$, (c) $30°$ 2. (a) $\cot 75° = \frac{1}{\tan 75°}$, (b) undefined, (c) $\tan\left(\frac{\pi}{8}\right) = \frac{\sin\left(\frac{\pi}{8}\right)}{\cos\left(\frac{\pi}{8}\right)}$
Answer for screen readers
- (a) $60° \equiv \frac{\pi}{3} \text{ rad}$
(b) $3.57 \text{ rad} \equiv 204.25°$
(c) $\frac{\pi}{6} \equiv 30°$ - (a) $\cot 75° = \frac{1}{\tan 75°}$
(b) $\tan(\frac{25\pi}{2})$ is undefined
(c) $\tan\left(\frac{\pi}{8}\right) = \frac{\sin\left(\frac{\pi}{8}\right)}{\cos\left(\frac{\pi}{8}\right)}$
Steps to Solve
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Convert 60° into radians and degrees To convert degrees to radians, use the conversion factor: $$ R = D \times \frac{\pi}{180} $$ For 60°: $$ R = 60 \times \frac{\pi}{180} = \frac{\pi}{3} \text{ rad} $$
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Convert 3.57 into degrees and radians First, convert 3.57 radians into degrees using: $$ D = R \times \frac{180}{\pi} $$ For 3.57: $$ D = 3.57 \times \frac{180}{\pi} \approx 204.25° $$
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Convert $\frac{\pi}{6}$ into degrees and radians To convert radians to degrees: $$ D = R \times \frac{180}{\pi} $$ For $\frac{\pi}{6}$: $$ D = \frac{\pi}{6} \times \frac{180}{\pi} = 30° $$
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Evaluate cot 75° Using cotangent, we have: $$ \cot 75° = \frac{1}{\tan 75°} $$
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Evaluate tan $\frac{25\pi}{2}$ Since $\frac{25\pi}{2}$ is greater than $2\pi$, reduce it by subtracting $12\pi$ (since $2\pi \approx 6.28$): $$ \frac{25\pi}{2} - 12\pi = \frac{\pi}{2} $$ Thus: $$ \tan\left(\frac{25\pi}{2}\right) = \tan\left(\frac{\pi}{2}\right) \text{ (undefined)} $$
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Evaluate tan $\frac{\pi}{8}$ Using the definition of tangent: $$ \tan\left(\frac{\pi}{8}\right) = \frac{\sin\left(\frac{\pi}{8}\right)}{\cos\left(\frac{\pi}{8}\right)} $$
- (a) $60° \equiv \frac{\pi}{3} \text{ rad}$
(b) $3.57 \text{ rad} \equiv 204.25°$
(c) $\frac{\pi}{6} \equiv 30°$ - (a) $\cot 75° = \frac{1}{\tan 75°}$
(b) $\tan(\frac{25\pi}{2})$ is undefined
(c) $\tan\left(\frac{\pi}{8}\right) = \frac{\sin\left(\frac{\pi}{8}\right)}{\cos\left(\frac{\pi}{8}\right)}$
More Information
- The conversion between degrees and radians is essential in trigonometry, especially for calculus and integration.
- The cotangent function represents the reciprocal of the tangent function.
Tips
- Confusing the order of operations when evaluating trigonometric expressions.
- Forgetting to convert angles properly between radians and degrees.
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