20 True or False 1 point Verify that \( \frac{\sec x \sin x}{\csc x \cos x}=\tan ^{2} x \) is an identity. True False

6 The graph \( y=a+b \cos (c x) \) is defined for \( 0 \leq x \leq 2 \pi \), where \( a, b \) and \( c \) ar constants. The graph has a period of \( \frac{4 \pi}{3} \) and a minimum value of 1 when \( x=\frac{4 \pi}{3} \). The graph also passes through the point \( \left(\frac{\pi}{3}, 3\right) \). (a) Show that \( a=3, b=-2 \) and \( c=\frac{3}{2} \).

4 ¿Cuál es el valor del ángulo absoluto del vector? (Escriba solo el valor, sin la unidad \( { }^{\circ} \) ) * \( \vec{b}=6.8 \mathrm{Km}, 83^{\circ} \) al SOe

For what values of the angle between \( \vec{A} \) and \( \vec{B} \) will the dot product \( \vec{A} \vec{B} \) be positive, negative or zero?

4. Numeric 15 points \( \begin{array}{l}\text { 2. A construction worker leans his ladder } \\ \text { against a building making a } 60^{\circ} \text { angle with } \\ \text { the ground. If his ladder is } 20 \text { feet long, how } \\ \text { far away is the base of the ladder from the } \\ \text { building? Round to the nearest tenth. }\end{array} \) Type your answer...

ind \( \tan ^{-1}(-\sqrt{3}) \)