A student is given four different trigonometric expressions 1 I secx cosx 9 II cot²x-csc² x III 2cos²x+2sin²x 2 cos x IV 2 cotx- sin x If the expression are simplified are ranked, from smallest to largest, what is the correct order? Show all the steps and state the name of appropriate formula you used in each step. For example: III: 2cos²x + 2sin²x = 2(cos²x+sin²x) = 2 (1) This step uses Pythagorean identity. = 2 The names of formula you might required are: Cofunction formula / compound angle formula (for sine, cosine, tangent) / double angle formula (for sine, cosine, tangent) / reciprocal identities / quotient identities / Pythagorean identities / etc.