state the domain and range of the following: y = 3x/(2x-5)
Domain: (-infinity, 5/2)U(5/2, infinity) Range: (-infinity,infinity)
range all real numbers except \[\frac{3}{2}\]
no the range is all real numbers
Why is it all real numbers?
actually it is all real numbers except \[\frac{3}{2}\] you can see it because there is no way for that ratio to be equal to 3/2. you are off by the -5 in the denominator
another way to say this is that the function has a horizontal asymptote at 3/2, and while it is possible for a function to cross its asymptote it does not in this case
o yea ur right
calculus will show that the function is strictly decreasing, but you do not need calculus to see that there is no way for this fraction to be equal to 3/2
how can you tell it will never equal 3/2?
its the coefficients of the "x"s
but only if the numerators and denominators exponents are equal
ok the numerator is 3x the denominator is 2x-5 this ratio can never be equal exactly to 3/2 because whatever x is, it is the same on top and bottom. for the ratio to be exactly 3/2 that -5 would have to be gone
put say x = 100 you get 300/195 which is close to 3/2 but not exactly 3/2.
oh ok. Thank you very much
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