Trigonometry
Special Right Triangles
Find the exact value of cos 60* - cot 30* - cot 90*.

½ - sqrt(3)

Step-by-step explanation:

cos(60) = ½

tan(30) = 1/sqrt(3)

cot(30) = sqrt(3)

tan(90) is undefined

cot(90) = 0

½ - sqrt(3) -0

½ - sqrt(3)

the answer to this in exact form is 4/35 but in decimal form its 0.1142857

hope this if needed hmu

answer: the prove is mentioned below.

step-by-step explanation:

an isometric rigid transformation is a transformation of the plane that preserves lengths and angles.    

that is, the pre-image and the image under a rigid transformation will be congruent.

here, given: cb ║ ed and cb ≅ ed

prove that: δ cbf ≅ δ edf

since, cb ║ ed

therefore, by the alternative interior angle theorem,

∠fcb ≅ ∠fed

∠fbc ≅ ∠ fde

and, cb ≅ ed ( given)

therefore, the angles and sides are persevered after transformation.

thus, by the definition of isometric rigid transformation,

δ cbf ≅ δ edf