Consider the derivation of an alternate form of the cosine double angle identity. What is the error in this derivation?

In step 1, cos(2x) is equal to cos2(x) + sin2(x).
In step 2, sin2(x) should have been replaced with 1 + cos2(x).
In step 3, cos2(x) – 1 – cos2(x) should be cos2(x) – 1 + cos2(x).
In step 4, 2cos2(x) – 1 should be 1 – 2cos2(x).

You download a video game to your computer. you have a 60-minute free trial of the game. it takes 5 1/6 minutes to set up the game 7 1/3 minutes to play each level. you want to find out how many levels you can play for free.which inequality describes the number of levels, l, you can play in 60 minutes? can you play 6 levels during your free trial? i need ,

Isuck at math ; ^; m a student solved this problem and said the answer is 3 feet. chase had a roll of ribbon that contained 7 7/8  feet of ribbon. he cut off one piece that was 3 5/8  feet long and another piece that was 1 1/4  feet from the roll. how much ribbon was left on the roll? is the student's answer reasonable? yes, the answer is reasonable. no, the answer is not reasonable. it should be about 2 feet. no, the answer is not reasonable. it should be about 13 feet. no, the answer is not reasonable. it should be about 4 feet.

Which equation represents the function on the graph?