I need someone to help me with 1 question...also anyone wanna b friends?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

What is the missing reason in the proof? segment addition congruent segments theorem transitive property of equality subtraction property of equality?

Me its important ! marge runs an ice cream parlor. her speciality is triple chocolate sundaes.she can prepare 1 sundae every 2 minutes, and she earns $1.20 for each sundae she makes . if she just makes sundaes for a single shift of at most 4 hours and at least 2 hours , which function relates her earnings to the number of minutes she works?