Which of the following are graphs of functions?​

Given tan∅=4/3 and π< ∅< (3π)/2; find cos2∅ a. -24/25 b. 24/25 c. -24/7 d. -7/25

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles