1. Escribir cada una de las siguientes expresiones en terminos del seno \( \begin{array}{ll}\text { a) } \frac{\operatorname{sen} x+\tan x}{\sec x+1} & \text { b) } \frac{\sec ^{2} x-\tan ^{2} x}{\csc ^{2} x}\end{array} \)

a) \( \sin ^{4} x+\cos ^{2} x \cdot \sin ^{2} x-\sin ^{2} x \)

34. Diketahui segitiga ABC siku-siku di \( \mathrm{B}, \mathrm{a}=8 \mathrm{~cm} \) dan \( \mathrm{c}=6 \mathrm{~cm} \), maka nilai \( \sin A=\cdots \) a. \( \frac{4}{3} \) b. \( \frac{4}{5} \) c. \( \frac{5}{3} \) d. \( \frac{3}{5} \) e. \( \frac{3}{4} \)

8) \( y=-3 \cos 2 x \) NOTA: Las gráficas deben de tener como mínimo un periodo.

The angle of depression from one mountain summit to another is \( 15.9^{\circ} \). If the two mountains differ in height by 430 metres, find the horizontal distance between the two summits, to the nearest centimetre.

Given that \( \theta \) is an obtuse angle and \( \operatorname{cosec} \theta=k \), express, in terms of \( k \) (a) \( \cot \theta \)