(a) 4
(b) y = sqrt(9 - (9/16)x^2)
The best guess to the formula using knowledge of the general formula for an ellipse is:
x^2/16 + y^2/9 = 1
(a). An ellipse is reflectively symmetrical across both the major and minor axis. So if you can get the area of the ellipse in a quadrant, then multiplying that area by 4 would give the total area of the ellipse. So the factor of 4 is correct.
(b). The general equation for an ellipse is not suitable for a general function since it returns 2 y values for every x value. But if we restrict ourselves to just the positive value of a square root, that problem is easy to solve. So let's do so:
x^2/16 + y^2/9 = 1
x^2/16 + y^2/9 - 1 = 0
x^2/16 - 1 = - y^2/9
-(9/16)x^2 + 9 = y^2
9 - (9/16)x^2 = y^2
sqrt(9 - (9/16)x^2) = y
y = sqrt(9 - (9/16)x^2)
If the call cost 35 cents to use the card that leaves $12 that was from minutes. There is 4 quarters in a dollar, 12x4 is 48.
VERIFY:
$1=4
$2=8
$3=12
$4=16
$5=20
$6=24
$7=28
$8=32
$9=36
$10=40
$11=44
$12=48
Hey there
<span>240 times 365 can be written as 240 x 356.
</span><span>240 x 356 = </span>87600
Answered respectively;
1) 0.13514
2) 0.125
