Can someone please help me? I need it right now

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

Igor stravinsky tires sells approximately 3,760,000 car tires and 1,200,000 truck tires each year. about 47,000,000 care tires and 26,000,00 truck tires are sold each year in the united states. what is stravinsky's market share in each of these two markets (cars and trucks)?

If sin(x) = 0 and cos(x) = 1, what is tan(x)?