What is the range of an exponential parent function with the base 2

Sketch one cycle if the cosine function y=2cos2theta

Given: ae ≅ ce ; de ≅ be prove: abcd is a parallelogram. we have that ab || dc. by a similar argument used to prove that △aeb ≅ △ced, we can show that △ ≅ △ceb by. so, ∠cad ≅ ∠ by cpctc. therefore, ad || bc by the converse of the theorem. since both pair of opposite sides are parallel, quadrilateral abcd is a parallelogram.

Add. express your answer in simplest form. 12 9/10+2 2/3 = i need u guys to me find the answer to this question