Instrucciones: Responde las siguientes preguntas.

• Identifica la identidad trigonométrica correcta.
  • $$\frac{1}{1+ \mathop{\mbox{sen}}\nolimits x} = \frac{1- \mathop{\mbox{sen}}\nolimits x}{\cos^{2} x}$$
  • $$\frac{1}{1+ \mathop{\mbox{sen}}\nolimits x} = \frac{1- 4\mathop{\mbox{sen}}\nolimits x}{1- \mathop{\mbox{sen}}\nolimits x}$$
  • $$\frac{1}{1+ \mathop{\mbox{sen}}\nolimits x} = \csc x - \mathop{\mbox{sen}}\nolimits x$$
  • $$\frac{1}{1+ \mathop{\mbox{sen}}\nolimits x} = \tan x$$

• Identifica la identidad trigonométrica correcta.
  • $$\frac{1- \mathop{\mbox{sen}}\nolimits^{2} x}{\mathop{\mbox{ctg}}\nolimits x} = \tan^{2} x$$
  • $$\frac{1- \mathop{\mbox{sen}}\nolimits^{2} x}{\mathop{\mbox{ctg}}\nolimits x} = \mathop{\mbox{sen}}\nolimits x \cos x$$
  • $$\frac{1- \mathop{\mbox{sen}}\nolimits^{2} x}{\mathop{\mbox{ctg}}\nolimits x} = \mathop{\mbox{sen}}\nolimits x \tan x$$
  • $$\frac{1- \mathop{\mbox{sen}}\nolimits^{2} x}{\mathop{\mbox{ctg}}\nolimits x} = \mathop{\mbox{ctg}}\nolimits x$$

• Identifica la identidad trigonométrica correcta.
  • $$\frac{\mathop{\mbox{sen}}\nolimits x + \cos x}{\mathop{\mbox{sen}}\nolimits x - \cos x} = \frac{1- \cos^{2} x}{\csc^{2} x}$$
  • $$\frac{\mathop{\mbox{sen}}\nolimits x + \cos x}{\mathop{\mbox{sen}}\nolimits x - \cos x} = 1$$
  • $$\frac{\mathop{\mbox{sen}}\nolimits x + \cos x}{\mathop{\mbox{sen}}\nolimits x - \cos x} = \frac{\sec x + \csc x}{\sec x - \csc x}$$
  • $$\frac{\mathop{\mbox{sen}}\nolimits x + \cos x}{\mathop{\mbox{sen}}\nolimits x - \cos x} = 1-2\sec^{2} x$$

• Identifica la identidad trigonométrica correcta
  • $$\frac{\tan x - \mathop{\mbox{sen}}\nolimits x}{\mathop{\mbox{sen}}\nolimits^{3} x} = \mathop{\mbox{sen}}\nolimits x$$
  • $$\frac{\tan x - \mathop{\mbox{sen}}\nolimits x}{\mathop{\mbox{sen}}\nolimits^{3} x} = \frac{\sec x}{1+ \cos x}$$
  • $$\frac{\tan x - \mathop{\mbox{sen}}\nolimits x}{\mathop{\mbox{sen}}\nolimits^{3} x} = 1$$
  • $$\frac{\tan x - \mathop{\mbox{sen}}\nolimits x}{\mathop{\mbox{sen}}\nolimits^{3} x} = \sec x$$

• Identifica la identidad trigonométrica correcta
  • $$\frac{\mathop{\mbox{sen}}\nolimits x}{\sec^{2} x -1} = \sec x$$
  • $$\frac{\mathop{\mbox{sen}}\nolimits x}{\sec^{2} x -1} = \sec^{2} x$$
  • $$\frac{\mathop{\mbox{sen}}\nolimits x}{\sec^{2} x -1} = \csc^{2} - 2\mathop{\mbox{ctg}}\nolimits x$$
  • $$\frac{\mathop{\mbox{sen}}\nolimits x}{\sec^{2} x -1} = \cos x \mathop{\mbox{ctg}}\nolimits x$$