25. यदि लगाउनुहोस् । If \( 9 \cos \theta+40 \sin \theta=41 \), find the value of \( \tan \theta \).

QUESTION 6 Simplify the following expressions without using a calculator. \( \begin{array}{l}6.1 \quad \frac{\sin 210^{\circ} \cos 300^{\circ} \tan 240^{\circ}}{\cos 120^{\circ} \tan 150^{\circ} \sin 330^{\circ}} \\ 6.2 \\ {[\sin (-\theta)+\cos (360-\theta)]\left[\cos (90-\theta)+\frac{\sin \theta}{\tan \theta}\right]} \\ 6.3 \text { If } \tan x=m+\frac{1}{m}, 90^{\circ} \leq x \leq 270^{\circ} \text { and } m^{2}+\frac{1}{m^{2}}=1 \\ \text { Calculate the value of } x \text { without the use of a calculator. }\end{array} \)

(14) \( \sin \left(\theta-45^{\circ}\right)+\sin \left(\theta+45^{\circ}\right) \)

(3). \( \sin \left(x+45^{\circ}\right) \)

Soit \( A B C \) un triangle rectangle en B tel que \( : \cos \widehat{B A C}=\frac{3}{4} \) 11 Montrer que \( : \sin \widehat{B A C}=\frac{\sqrt{7}}{4} \) 2 Calculer : \( \tan \widehat{B A C} \) 3 Calculer : \( \sin \widehat{A C B}, \cos \widehat{A C B} \) et \( \tan \widehat{A C B} \) 4 On suppose que: \( A B=5 \mathrm{~cm} \). Calculer \( A C \)

Simplifier: \( B=3 \cos 10^{\circ}+5 \cos ^{2} 15^{\circ}+5 \cos ^{2} 75^{\circ}-3 \sin 80^{\circ} \)