Question: 01 Calcular:
(sec²45° + tan45°) . cot37° − 2cos60°
A)0 B)1 C)2 D)3 E)4
02 Calcular:
(tan60° + sec30° − sen60°) sec60°
A) 25/12 B) 25/24 C) 49/12 D) 49/24 E) 7/18
03 Calcular:
(tan37° + csc53°) / (sec45° + csc45°)
A) √2 B) 2√2 C) √2/2 D) √2/4 E) 1
04 Determine el valor de “x” en:
5x.sen53° − sec60° = 2x + (tan60° + cot30°)²
A)3 B)5 C)7 D)9 E)11
05 Calcular: E = √(a+b+c)
Siendo:
a = tan37° + csc53°
b = sen45° . sec45°
c = 2sen60°, tan30°
1. **Problema 01:** Calcular $$ (\sec^2 45^\circ + \tan 45^\circ) \cdot \cot 37^\circ - 2 \cos 60^\circ $$
2. **Fórmulas y valores importantes:**
- $$\sec 45^\circ = \frac{1}{\cos 45^\circ} = \sqrt{2}$$
- $$\tan 45^\circ = 1$$
- $$\cot 37^\circ = \tan (90^\circ - 37^\circ) = \tan 53^\circ$$ (aproximadamente 1.327)
- $$\cos 60^\circ = \frac{1}{2}$$
3. **Cálculo paso a paso:**
- $$\sec^2 45^\circ = (\sqrt{2})^2 = 2$$
- $$\sec^2 45^\circ + \tan 45^\circ = 2 + 1 = 3$$
- Multiplicamos por $$\cot 37^\circ$$:
$$3 \times 1.327 = 3.981$$
- Restamos $$2 \cos 60^\circ = 2 \times \frac{1}{2} = 1$$:
$$3.981 - 1 = 2.981 \approx 3$$
4. **Respuesta:** La opción correcta es D) 3
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1. **Problema 02:** Calcular $$ (\tan 60^\circ + \sec 30^\circ - \sin 60^\circ) \sec 60^\circ $$
2. **Valores trigonométricos:**
- $$\tan 60^\circ = \sqrt{3} \approx 1.732$$
- $$\sec 30^\circ = \frac{1}{\cos 30^\circ} = \frac{1}{\sqrt{3}/2} = \frac{2}{\sqrt{3}}$$
- $$\sin 60^\circ = \frac{\sqrt{3}}{2} \approx 0.866$$
- $$\sec 60^\circ = \frac{1}{\cos 60^\circ} = 2$$
3. **Cálculo:**
- $$\tan 60^\circ + \sec 30^\circ - \sin 60^\circ = 1.732 + \frac{2}{\sqrt{3}} - 0.866$$
- Convertimos $$\frac{2}{\sqrt{3}}$$ a decimal: $$\approx 1.155$$
- Suma: $$1.732 + 1.155 - 0.866 = 2.021$$
- Multiplicamos por $$\sec 60^\circ = 2$$:
$$2.021 \times 2 = 4.042$$
4. **Convertimos a fracción exacta:**
- $$\tan 60^\circ = \sqrt{3}$$
- $$\sec 30^\circ = \frac{2}{\sqrt{3}}$$
- $$\sin 60^\circ = \frac{\sqrt{3}}{2}$$
- Sumamos:
$$\sqrt{3} + \frac{2}{\sqrt{3}} - \frac{\sqrt{3}}{2} = \frac{2\sqrt{3}}{2} + \frac{2}{\sqrt{3}} - \frac{\sqrt{3}}{2} = \frac{2\sqrt{3} - \sqrt{3}}{2} + \frac{2}{\sqrt{3}} = \frac{\sqrt{3}}{2} + \frac{2}{\sqrt{3}}$$
- Combinamos en común denominador $$2\sqrt{3}$$:
$$\frac{\sqrt{3}}{2} = \frac{3\sqrt{3}}{2\sqrt{3}}$$
$$\frac{2}{\sqrt{3}} = \frac{4}{2\sqrt{3}}$$
- Suma:
$$\frac{3\sqrt{3} + 4}{2\sqrt{3}}$$
- Multiplicamos por $$\sec 60^\circ = 2$$:
$$2 \times \frac{3\sqrt{3} + 4}{2\sqrt{3}} = \frac{3\sqrt{3} + 4}{\sqrt{3}}$$
- Racionalizamos:
$$\frac{3\sqrt{3} + 4}{\sqrt{3}} \times \frac{\sqrt{3}}{\sqrt{3}} = \frac{3 \times 3 + 4 \sqrt{3}}{3} = \frac{9 + 4 \sqrt{3}}{3}$$
- Aproximadamente $$\approx 4.04$$, que corresponde a la opción C) 49/12 (ya que $$\frac{49}{12} \approx 4.083$$)
5. **Respuesta:** C) 49/12
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1. **Problema 03:** Calcular $$ \frac{\tan 37^\circ + \csc 53^\circ}{\sec 45^\circ + \csc 45^\circ} $$
2. **Valores trigonométricos:**
- $$\tan 37^\circ \approx 0.753$$
- $$\csc 53^\circ = \frac{1}{\sin 53^\circ} \approx \frac{1}{0.799} = 1.251$$
- $$\sec 45^\circ = \sqrt{2} \approx 1.414$$
- $$\csc 45^\circ = \frac{1}{\sin 45^\circ} = \sqrt{2} \approx 1.414$$
3. **Cálculo:**
- Numerador: $$0.753 + 1.251 = 2.004$$
- Denominador: $$1.414 + 1.414 = 2.828$$
- División: $$\frac{2.004}{2.828} \approx 0.708$$
4. **Comparación con opciones:**
- $$\frac{\sqrt{2}}{2} = \frac{1.414}{2} = 0.707$$
5. **Respuesta:** C) $$\frac{\sqrt{2}}{2}$$
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1. **Problema 04:** Determinar $$x$$ en:
$$5x \sin 53^\circ - \sec 60^\circ = 2x + (\tan 60^\circ + \cot 30^\circ)^2$$
2. **Valores trigonométricos:**
- $$\sin 53^\circ \approx 0.799$$
- $$\sec 60^\circ = 2$$
- $$\tan 60^\circ = \sqrt{3} \approx 1.732$$
- $$\cot 30^\circ = \sqrt{3} \approx 1.732$$
3. **Calculamos el cuadrado:**
- $$\tan 60^\circ + \cot 30^\circ = 1.732 + 1.732 = 3.464$$
- $$ (3.464)^2 = 12$$
4. **Sustituimos:**
- $$5x \times 0.799 - 2 = 2x + 12$$
- $$3.995x - 2 = 2x + 12$$
5. **Despejamos $$x$$:**
- $$3.995x - 2x = 12 + 2$$
- $$1.995x = 14$$
- $$x = \frac{14}{1.995} \approx 7.02$$
6. **Respuesta:** C) 7
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1. **Problema 05:** Calcular $$E = \sqrt{a + b + c}$$ con:
- $$a = \tan 37^\circ + \csc 53^\circ$$
- $$b = \sin 45^\circ \cdot \sec 45^\circ$$
- $$c = 2 \sin 60^\circ \cdot \tan 30^\circ$$
2. **Valores trigonométricos:**
- $$\tan 37^\circ \approx 0.753$$
- $$\csc 53^\circ \approx 1.251$$
- $$\sin 45^\circ = \frac{\sqrt{2}}{2} \approx 0.707$$
- $$\sec 45^\circ = \sqrt{2} \approx 1.414$$
- $$\sin 60^\circ = \frac{\sqrt{3}}{2} \approx 0.866$$
- $$\tan 30^\circ = \frac{1}{\sqrt{3}} \approx 0.577$$
3. **Calculamos cada término:**
- $$a = 0.753 + 1.251 = 2.004$$
- $$b = 0.707 \times 1.414 = 1.000$$
- $$c = 2 \times 0.866 \times 0.577 = 1.000$$
4. **Sumamos:**
- $$a + b + c = 2.004 + 1.000 + 1.000 = 4.004$$
5. **Calculamos $$E$$:**
- $$E = \sqrt{4.004} \approx 2$$
6. **Respuesta:** $$E \approx 2$$