BEC'S methods questions

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To weigh over 120kg:

normcdf(120,1E99,157.334,68.123)=0.708

hence, the probability of between 30 and 50 penguins (assuming you have 50 or more to start off from)

y1=binomcdf(x,0.708,30,50)

go into table and find the first case greated than 0.65 (which incidently, happens to be 44, so didn't think the question through, DivideBy0 , or I've gone terribly wrong somewhere)

Hehe... sorry I thought the question up on the spot, no wonder it turned out odd :p

Yeah, I tried that but my table only has one column: "x".

I checked to see if I could store it to l1 (which is the name of a column in my stat/list editor) but all that achieved was deleting the l1 column.

So now I have two questions:
1. How do you get the L1 column back...
2. How do you use a table to find "n"

Thanks

For your first question, in Stats/List choose F1 -> 3: Setup Editor
In the box next to "Lists to view", type

Code: [Select]

list1,list2,list3,list4,list5,list6 for example if you want 6 lists.

[bec]

Thanks DivideBy0, that worked and it's fixed now.

Does anyone know of a non-painful way of doing addition of ordinates? Eg. 4sin2x-3cosx
The way I do it is pretty tedious: I usually just find the points where one of the functions=0, then choose points where the functions = whole numbers and add/subtract them, then smooth it all over ensuring that I've got turning points in
Is there a better way?

Thanks

[Collin Li]

I can't think of any new paradigmal way, but here are a few additional techniques:

- When they intersect, make sure you double that up.
- Try to find where they "nullify" (a positive value and a negative value adding up the zero).
- Try to visualise the tangents of both curves as you trace through, and when they are nullify each other, that's your stationary point.

[bec]

I can't think of any new paradigmal way

...and he calls himself a tutor

haha thanks for that though, I hadn't thought of the tangent thing - it helps!

[Mao]

Does anyone know of a non-painful way of doing addition of ordinates? Eg. 4sin2x-3cosx
The way I do it is pretty tedious: I usually just find the points where one of the functions=0, then choose points where the functions = whole numbers and add/subtract them, then smooth it all over ensuring that I've got turning points in
Is there a better way?

addition of ordinates is always painful (thats why we have computers and calculators to do it for us).
the method you have described is good, but also keep in mind that you are not limited to using solely the addition of ordinates to find your graph. so if the function is easy to differentiate, do so and find turning points.

[bec]

Yeah thanks Mao, I normally do that but the Qs I've been looking at this morning have been hard to differentiate/not worth it.

Another question, I know this isn't complicated, but how do you simplify ? (don't know how to write it in latex but the x and x² are the bases of the logs)
thanks

[Collin Li]

Code: [Select]

\frac{\log_{x}11}{\log_{x^2}11}


Let



Let

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[bec]

Code: [Select]

\frac{\log_{x}11}{\log_{x^2}11}


Let



Let

This is harder than I thought...can you show me how x^2q = 11?

Also, I don't really understand how I could use this:

to work it out... ?

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Also, I don't really understand how I could use this:

to work it out... ?

[Collin Li]

Let

[bec]

Ohhhhhhh, I get it! Thanks!

[Mao]

very nice =]

i shall remember that

[bec]

Is this a valid way of simplifying it:







I don't know if I just invented a new log law for the purposes of this question or if it's right...

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Is this a valid way of simplifying it:







I don't know if I just invented a new log law for the purposes of this question or if it's right...

Edit: Thanks Mao

Yep