Domain question :S (1 Viewer)

[MrBrightside]

Find the domain of y = root x^2 - x - 2

 

[MrBrightside]

Re: Also Range question :S

y = -x^2 + 7x - 6 in the domain 0 greater than or equal to x less than or equal to 7

 

[Ferox]

Re: Also Range question :S

The square root has to be ≥ 0

Therefore
x^2 - x - 2 ≥ 0
(x-2)(x+1)≥0

x≥2; x≤-1

That's the domain.

 

[Ferox]

Re: Also Range question :S

For the range question.
y=-(x-6)(x-1)

From the graph it's evident the lowest value of y is -6 at x=0 and x=7, and the highest value of y is at the vertex, x=7/2
f(7/2)=-(7/2-6)(7/2-1)
=25/4

Therefore range: -6≤y≤25/4

 

[hscishard]

Re: Also Range question :S

For the range question.
y=-(x-6)(x-1)

From the graph it's evident the lowest value of y is -6 at x=0 and x=7, and the highest value of y is at the vertex, x=7/2
f(7/2)=-(7/2-6)(7/2-1)
=25/4

Therefore range: -6≤y≤25/4

First question is correct.

Range however should be y>= 0 as it's a sqaure root.
You got the concept right for other questions but its just not used for this one.

 

[hscishard]

Omg wtf. Two questions in two posts?
Sorry you were right on both.

 

[MrBrightside]

yea his right, thx every1 understand it now