Schoolwork Help Thread

[mikey]

-1(a+b+c=48)
a4+b2+c=60
add those 2 together
a(3)+b=12 <save this

now add -1(a+b+c=48) with a9 + b3 + c = 40
a(8 )+b(2)=-8

-2(a(3)+b=12)
a(2)=-32
a=-16

(-16)(3)+b=12
b=60

(-16)+(60)+c=48
c=4

y=-16x**+60x+4  So your equation is certainly right ^
plugging it into my calculator I get a vertex of (15/8,241/4)

[FireArrow]

...but, the points we plugged in have y values of 40, 48, and 60, which aren't on the line of the equation.

[Maelstrom]

I'm not sure plugging numbers into a TI will take acceleration due to gravity into effect.
It would probably assign a different number that made it fit the points better.

[Mashi]

...but, the points we plugged in have y values of 40, 48, and 60, which aren't on the line of the equation.

They don't need to be for a curve of best fit.  All data are subject to measurement error, so it's impossible for all your data to perfectly fit onto a predicted general formula.  To give you an example, if my data were (0, 0), (1, 1), and (2, 2.1) and I was expected to make a line of best fit (i.e. y = mx), it would be impossible to have it pass through all three points (the best that can be done is through two of them with the equation y=x and even then, it wouldn't be the line of best fit).  So your equation is correct, don't worry.  It's the curve of best fit, not the curve of including-all-points-of-the-data.

Barring air resistance and other miscellaneous forces, the effects due to gravity cause projectile motion to follow the path of a parabola, so there's no need to worry about gravity being excluded from your equations.

[FireArrow]

Damn, then this problem is complete bs, because it later asks "At what time does the ball reach 54 ft" which is impossible because it never does. :/

[mikey]

Mathi saves the day

Damn, then this problem is complete bs, because it later asks "At what time does the ball reach 54 ft" which is impossible because it never does. :/

but if the maximum is 60.25 then it has to reach 54 ft

[FireArrow]

Oh yeah, forgot that -b/2a was for the x value not y .-.

Thanks guys! Sorry about that....

[KefkaticFanatic]

Use this for schoolwork or whatever other academic problems guys.

[BlackDragonSlayer]

I think I already have the correct answer for this, but I'm not 100% certain I do.

8 ln (x - 9) = 1

[Maelstrom]

e^1/8 -- 9
Yeah mental math.

[mikey]

that's not even math bro you're just moving it from log form to exponent form

[Jub3r7]

The question in class I believe asked for the slope of the tangent line to an equation that represented an object's movement, and it gave the equation along with the object's instantaneous velocity at t=0.
So the teacher plugs in (1/2) for t, located at the bottom of the curve in the equation's graph, and uses that as the second point in the average velocity equation with t=0 as the first point.

I ask him later how he chose 1/2, and his response was along the lines of " I just did ," but maybe I just misunderstood him?
idk, I'll see if the question comes up again in class tomorrow, if it does then I'll copy it down and post it here.

[Bubbles]

Nah, if your physics teacher is anything like mine you probably heard correctly. I really hope physics teachers aren't notoriously arrogant and unhelpful, because I'm planning on majoring in physics :/ I'd try to help you but there's probably someone else who has a whole lot more of an idea how physics works than me

[braix]

I love my Algebra teacher cuz he sucks.
He gives us homework, then sits at his desk and uses his phone. So I'm able to take out some snacks and quietly eat them while browsing the forums on my phone or whatever and he won't notice at all.

[blueflower999]

I love my Algebra teacher cuz he sucks.
He gives us homework, then sits at his desk and uses his phone. So I'm able to take out some snacks and quietly eat them while browsing the forums on my phone or whatever and he won't notice at all.

Sounds like my English teacher only he somehow manages to make the class brutally difficult and put no effort in whatsoever.

Our mid-term involved 50 multiple choices questions followed by three five-paragraph essays that took seven sides of paper. >.<