At a given level of effort, it is reasonable to assume that the rate at which fish are caught depends on the population y: the more fish there are, the easier it is to catch them. thus we assume that the rate at which fish are caught is given by ey, where e is a positive constant, with units of 1/time, that measures the total effort made to harvest the given species of fish. to include this effect, the logistic equation is replaced by dy/dt = r(1 − y/k)y − ey. (i) this equation is known as the schaefer model after the biologist m. b. schaefer, who applied it to fish populations. (a) show that if e < r, then there are two equilibrium points, y1 = 0 and y2 = k(1 − e/r) > 0. (b) show that y = y1 is unstable and y = y2 is asymptotically stable.

Comedians like to joke that the reason we haven’t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earth’s broadcasts of intellectually embarrassing tv programs, like gilligan’s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. let’s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame

An electric clothes dryer has a resistance of 8 ohms. it draws 30 a of current. what is the voltage, in volts, of the wall outlet that it is plugged into?

What does si stand for,when referring to a system of measurement