1) \( A=\cos ^{2} 40^{\circ}+\cos ^{2} 50^{\circ}+\tan 250 \times \cos 65^{\circ} \) 2) \( B=\cos ^{2} x \times \tan ^{2} x+\cos ^{2} s x \)

If \( \tan \frac{a}{b}=1 \), then \( \tan \frac{2 a}{3 b}=\ldots \ldots \ldots \ldots \) \( \begin{array}{llll}\text { (a) } \frac{1}{2} & \text { (b) } \frac{1}{\sqrt{3}} & \text { (c) } \frac{2}{3} & \text { (d) } \sqrt{3}\end{array} \)

Si el seno de un ángulo es \( \frac{3}{5} \), ¿cuál es el valor de su cosecante?

30. If \( x-a(\operatorname{cosec} \theta+\cot \theta) \) and \( y=\frac{b(1-\cos \theta)}{\sin \theta} \), then \( x y \)

5.2 Determine the following with the aid of a calculator 5.2.1 \( \quad \) the size of the angle \( \alpha \). 5.2.2 the area of the \( \triangle P O X \) if it given that \( \mathrm{X}(2 ; 0) \)

(22) If ABC is a triangle in which : \( 5 \sin \mathrm{~A} \sin \mathrm{~B}=6 \sin \mathrm{~B} \sin \mathrm{C}=9 \sin \mathrm{C} \sin \mathrm{A} \), then \( \mathrm{m}(\angle \mathrm{C})= \) \( \begin{array}{llll}\text { (a) } 28 & \text { (b) } 32 & \text { (c) } 36 & \text { (d) } 42\end{array} \) (23) If ABC is a triangle in which \( \cdot 6 a=4 h=3 c \), then the measure of the smallest