Which derivation correctly uses the cosine sum identity to prove the cosine double angle identity?.

Afish fossil is found in a rock. a foot bone and tooth are found in an older layer of the same rock. what can scientists learn from the rock? a) the area changed from land to water. b) the area changed from water to land. c) the area has always been land. d) the area was once an ocean.

When amy exercises in her fitness center for 1 hr she burns a total of 475 calories.if she burns 9 calories a minute jogging on the treadmill and then burns 6.5 calories a minute pedaling on the stationary bicycle how many minutes of the hour does she spend exercising on the bicycle?

Suppose you live in location a, a part of the united states with a semiarid climate . you travel to location b, which is in a neighboring area . there you would find a humid continental climate. in which direction is location b likely to be , relative to location a? what is an explanation for the difference