Which of the following is an equation of a curve that intersects at right angles every curve of the family y=(1/x)+k (where k takes all real values)?
a. y=-x
b. y=-x^2
c. y=(-1/3)x^3
d. y= (1/3)x^3
e. y=lnx

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)

Select the graph of the solution. click until the correct graph appears. |x| = 3

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?