/sci/ - Science & Math

y<= 4

go figure

homework fag

The answer is obviously 42

Could do it, but im not in the mood =P

>>1185989

Please? :D

You misspelled Death=Adder.

(x-5)(x+1)

durr

f(x)=(x-1)(x-5). solve for = +-4 and set intervall

>>1186045
+1 of course

>>1186045


Question, why would you solve for -4

>>1186050

i read it as abs(f(x)) <= 4

Sorry, but english is my 2. language

http://www.wolframalpha.com/input/?i=y%3D(x-5)*(x%2B1)+solve+for+x+when+y%3C4++

is this enough for you?

(x+1)(x-5) = 0
(x^2 -5x + x -5) = 0
(x^2 -4x -5) = 0

x^2-4x-5=0
Domain: {ℝ}
Range: {ℝ ≤ 4}

use 1/a(y-k)=(x-h)^2

>>1186050

To clarify further. If you are looking to define a function that has said intercept points, but have abs(f(x)) <=4 it is possible to have a quad. that has more than -4 in the intervall between the intercepts. also negative sign.
In most cases it is simple to see wether it is that way, but evaluating it for -4 will tell you straigh away

y=ax²+bx+c
y' = 2ax +b
max when 2ax +b =0
2ax+b=0 -> x= -b/(2a)

4 = a(-b/(2a))² - b (-b/(2a))+c
4 = b²/(4a) - 2b²/(4a)+c
4 = -b²/(4a)+c

If x=-1, y=0, so
a*(-1)² -b +c =0
a-b+c=0


If x=5, y=0, so
25a+5b+c=0
4 = -b²/(4a)+c

Now you have three equations with three unknowns:

a-b+c=0
25a+5b+c=0
4 = -b²/(4a)+c

Solve for a,b and c to get a = -4/9, b = 16/9, c = 20/9

So the formula is y= -4x²/9+16x/9+20/9

>>1186194
Other method:

y= a (x+1)(x-5)
a (x²-4x-5) =0
ax²-4ax-5=0
y' = 2ax-4a
2ax-4a =0
2a (x-2)=0
x=2
a(2+1)(2-5) = 4
a=-4/9

so y = -4/9 (x+1)(x-5)

>>1186228

Thank you very much!!!