Question

Match the correct differential equation to the graph. pls help me check (:

Answer 1

the answer is C. isit?

Answer 2

look at the graph, it has a local maximum in 'first quadrant'
that means, y' must have a zero in first quadrant (x>0, y >0)

Answer 3

having figured that out, look at equation A : y' = 1+xy
can this guy become 0 ever in first quadrant ? that is when x and y both are positive ?

Answer 4

nope.
similarly -2xy can never be 0 in first quadrant.

Answer 5

1-2xy can be 0 in first quadrant : 1-2xy = 0 => xy = 1/2
so oly C can be the potential solution

Answer 6

see if that makes more or less sense hmm

Answer 7

haha so i guessed it right! woo! haha xD i just thought x will most likely be 0.5 in equation c. haha but thanks to the correct explanation(:

Answer 8

yes thats really a good observation ! when x = 0.5 and y = 1, y' = 0 :)