Instrucciones: Responde las siguientes preguntas.

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

• Identifica la identidad trigonométrica correcta.
  • $$\left ( 1- \cos^{2} x \right )\left ( 1+ \mathop{\mbox{ctg}}\nolimits^{2} x \right ) = \cos x \mathop{\mbox{ctg}}\nolimits x$$
  • $$\left ( 1- \cos^{2} x \right )\left ( 1+ \mathop{\mbox{ctg}}\nolimits^{2} x \right ) = \sec x$$
  • $$\left ( 1- \cos^{2} x \right )\left ( 1+ \mathop{\mbox{ctg}}\nolimits^{2} x \right ) = 1$$
  • $$\left ( 1- \cos^{2} x \right )\left ( 1+ \mathop{\mbox{ctg}}\nolimits^{2} x \right ) = \mathop{\mbox{sen}}\nolimits x$$

• Identifica la identidad trigonométrica correcta.
  • $$\left ( \mathop{\mbox{sen}}\nolimits x - \csc x \right )^{2} = 2\csc^{2} x$$
  • $$\left ( \mathop{\mbox{sen}}\nolimits x - \csc x \right )^{2} = \sec x \csc x$$
  • $$\left ( \mathop{\mbox{sen}}\nolimits x - \csc x \right )^{2} = \mathop{\mbox{ctg}}\nolimits x$$
  • $$\left ( \mathop{\mbox{sen}}\nolimits x - \csc x \right )^{2} = \mathop{\mbox{ctg}}\nolimits^{2} x - \cos^{2} x$$

• Identifica la identidad trigonométrica correcta.
  • $$\mathop{\mbox{sen}}\nolimits x \left ( \tan x + \mathop{\mbox{ctg}}\nolimits x \right ) = \mathop{\mbox{sen}}\nolimits x \cos x$$
  • $$\mathop{\mbox{sen}}\nolimits x \left ( \tan x + \mathop{\mbox{ctg}}\nolimits x \right ) = \mathop{\mbox{sen}}\nolimits^{2} x \mathop{\mbox{ctg}}\nolimits x$$
  • $$\mathop{\mbox{sen}}\nolimits x \left ( \tan x + \mathop{\mbox{ctg}}\nolimits x \right ) = \sec x$$
  • $$\mathop{\mbox{sen}}\nolimits x \left ( \tan x + \mathop{\mbox{ctg}}\nolimits x \right ) = \mathop{\mbox{sen}}\nolimits^{2} x$$

• Identifica la identidad trigonométrica correcta.
  • $$\left ( 1+ \mathop{\mbox{sen}}\nolimits x \right )\left ( \sec x - \tan x \right )^{2} = 1- \mathop{\mbox{sen}}\nolimits x$$
  • $$\left ( 1+ \mathop{\mbox{sen}}\nolimits x \right )\left ( \sec x - \tan x \right )^{2} = \cos^{2} x$$
  • $$\left ( 1+ \mathop{\mbox{sen}}\nolimits x \right )\left ( \sec x - \tan x \right )^{2} = 1$$
  • $$\left ( 1+ \mathop{\mbox{sen}}\nolimits x \right )\left ( \sec x - \tan x \right )^{2} = \mathop{\mbox{sen}}\nolimits^{2} x$$