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2013-08-15 10:39:10 -0600 answered a question Computing derivatives

You are perfectly right. I defined sqrt as math.sqrt at the very beginning of my session. I completely forget that this is still included.

Thanks a lot!

2013-08-15 06:46:42 -0600 asked a question Computing derivatives

Hey guys,

I dont know where the problem is, but sage (5.10 here) doesnt compute easy derivatives as e.g.

x = var('x')
f = sqrt(x)
diff(f,x)

This leads to the following error: TypeError: unable to simplify to float approximation

Whats the problem here?

2013-08-05 09:08:03 -0600 asked a question mod 1 arithmetic

Hi all,

is it possible, to do simple mod 1 evaluations? For example, Mathematica outputs

N[1/2*(1 + Sqrt[5])^100 mod 1] ~ 0.9999999999999999999987374...

but

n(Mod(1/2*(1 + sqrt(5))^100,1))

(or similar attempts) in Sage result in

TypeError: unable to convert x (=1/2*(sqrt(5) + 1)^100) to an integer

Cheers, Markus

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2013-04-12 05:32:51 -0600 asked a question Quadratic number fields

Hello!

I try to implement an inclusion test, of which I thought it must be quite simple, but until now I cannot figure out how to do it properly. Problem: Given any element x, test if x is included in some quadratic number field and return true/false. I tried the following:

x = 2 + sqrt(5)
K = QuadraticField(5)
print(x in K)

Here, the answer is 'no' or 'false' which is obviously wrong, so I assume I'm doing something completely wrong. What do I have to change?

2013-02-13 07:53:25 -0600 answered a question Disabling y-axes in 2-D plot

The problem seems to be that I already have a very complicated plot, so I cannot apply matplotlib methods to that (at least I wouldnt know how).

The workaround you mentioned would be enough for me, but actually it doesnt work, because the white x-axes partly lies over the horizontal arrow and the y-axes lies over parts of the plot :/

I really thought that disabling axis seperately is a standard feature. Maybe I switch back to another CAS for this special plot :(

Thanks anyway for your answer.

2013-02-13 03:55:04 -0600 asked a question Disabling y-axes in 2-D plot

Hi all,

is it possible to switch of the y-axes seperately in a 2-D plot? The intuitive way

plot(exp,axes=[True,False])

is the very same as

plot(exp,axes=True)

Greetings, Markus

2013-02-06 06:51:53 -0600 asked a question No fillalpha after eps export?

Hey guys,

this is a slightly modified example from the sage help pages:

(plot(1+e^(-x^2), xmin=-2, xmax=2, ymin=0, ymax=2.5, fill=0.5, fillcolor='green', fillalpha=0.5)).save('t.eps')

It shows an exponential function which is filled from below by green color. The option fillalpha=0.5 should make this filling slightly transparent, which works perfectly when exporting to pdf, but repdroducably fails when exporting to eps. Is there any workaround?