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# C3 Range Question watch

1. How do I find the range of the function? I know the range is the value y takes, so should I sub x = 0 into the equation? How do I know which way the inequality arrows go?

Thanks
2. look at the graph. where can y go and not go (look at the asymptote)

if you have x tending to negative infinity what happens to y and if you have x tending to infinity what happens to y.
3. (Original post by w4rtorn)
look at the graph. where can y go and not go (look at the asymptote)

if you have x tending to negative infinity what happens to y and if you have x tending to infinity what happens to y.
Sorry, I still don't understand.

The range can't be less than the asymptote?

Y crosses at 4?
4. (Original post by gottastudy)
Sorry, I still don't understand.

The range can't be less than the asymptote?

Y crosses at 4?
Y never crosses 4, hence the asymptote. basically y can't be lower than four because however small x is e^(2x) will always be positive and as x tends to negative infinity 2e^(2x) will tend to 0 and so 2e^(2x)+4 will tend to 4. that's why the graph looks the way it does. so whatever x is y will always be bigger than 4. y>4
5. (Original post by w4rtorn)
Y never crosses 4, hence the asymptote. basically y can't be lower than four because however small x is e^(2x) will always be positive and as x tends to negative infinity 2e^(2x) will tend to 0 and so 2e^(2x)+4 will tend to 4. that's why the graph looks the way it does. so whatever x is y will always be bigger than 4. y>4
I see...Thank you for the explanation.

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