Expert: Sherman D. - 4/25/2007

Question
Hiya i wanted to sketch a graph of the parabolic curve, but before i wanted to
solve the quadractic equation first.

i need to see how your answer ends with these....

please advice

question1

solve the quadractic equation, in each case sketch a graph of the parabolic
curve.

(i) 4x^2 -144=0

(ii)  x^2-20x+91=0

(ii) x^2-4x-21=0

For the quadratic equation, i wanted to know the final equation to use to draw
table and graph.



Question 2

Sketch graphs of the function.

i wanted to see you final equation for these questions.i know how to work it
out i just desperately need to know its correct.

(i) (x+2)(x+1)(x-4)

(ii) (x-2)(x+4)(x-6)

(iii) y=e^2x


hope to hear from you.

regards

pearl  

Answer
for a graph, go to www.calculator.com/calcs/GCalc.html

(i)
4x^2 - 144=0
4(x^2 - 36) = 0
4(x - 6)(x + 6) = 0
x = 6 or -6

for the graph, type in 4x^2 - 144

------------------

(ii)  
x^2 - 20x + 91 = 0

x = (-b ± sqrt(b^2 - 4ac))/(2a)

x = (-(-20) ± sqrt((-20)^2 - 4(1)(91)))/(2(1))
x = (20 ± sqrt(400 - 364))/2
x = (20 ± sqrt(36))/2
x = (20 ± 6)/2
x = (14/2) or (26/2)
x = 7 or 13

for a graph, type in x^2 - 20x + 91

----------------------


(ii)
x^2 - 4x - 21 = 0
(x - 7)(x + 3) = 0
x = 7 or -3

For a graph, type in x^2 - 4x - 21

If at anytime you have a -x^2, you have to either write it in like this -1x^2 or -(x^2), or the graph won't come up like it suppose to.

-----------------------------------------------------------

(i)
(x + 2)(x + 1)(x - 4)
(x^2 + 2x + x + 2)(x - 4)
(x^2 + 3x + 2)(x - 4)
x^3 - 4x^2 + 3x^2 - 12x + 2x - 8
x^3 - x^2 - 10x - 8

for a graph, type in x^3 - x^2 - 10x - 8

---------------------

(ii)
(x - 2)(x + 4)(x - 6)
(x^2 + 4x - 2x - 8)(x - 6)
(x^2 + 2x - 8)(x - 6)
x^3 - 6x^2 + 2x^2 - 12x - 8x + 48
x^3 - 4x^2 - 20x + 48

for a graph, type in x^3 - 4x^2 - 20x + 48

-----------------------------

(iii)
y = e^2x
y = e^(2x) or y = (e^2)^x

for a graph, type in e^(2x)

also for values at the graph site, click the Trace button, and move your curser to line up with the marks.