Discrete-time signals with different frequencies can be equal; this is one manifestation of aliasing and folded aliases. Determine which of the following discrete-time cosine signals are equal (i. e., plots of xi[n]versus n will be identical):

x_1[n] = cos (0.9pi n + 0.1pi)
x_2[n] = cos (-2.9pi n + 0.1pi)
x_3[n] = cos (5.1pi n - 0.1pi)
x_4[n] = cos (6.9pi n - 0.1pi)
x_5[n] = cos (-7.1pi n - 0.1pi)

Apiston-cylinder with a volume of 0.25 m3 holds 1 kg of air (r 0.287 k/kgk) at a temperature of 100 c. heat transfer to the cylinder causes an isothermal expansion of the piston until the volume triples. how much heat is added to the piston-cylinder?

Two flowing streams of argon gas are adiabatically mixed to form a single flow/stream. one stream is 1.5 kg/s at 400 kpa and 200 c while the second stream is 2kg/s at 500 kpa and 100 ? . it is stated that the exit state of the mixed single flow of argon gas is 150 c and 300 kpa. assuming there is no work output or input during the mixing process, does this process violate either the first or the second law or both? explain and state all your assumptions.

Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan