## 891 Reputation

13 years, 62 days

## @cnheying  it is just a warning, th...

it is just a warning, the solution is still there. You can suppress the warning with

interface(warnlevel=0):

## @Alejandro Jakubi  unfortunately th...

unfortunately the typesetting details are not well documented. For instance, how can I increase the verical distance between x and y?

But now I have something to work with, thanks.

## ...

@nm

I was not aware of intsolve. Help pages says this command is just for linear integral equations,

## Patterns...

Hi,

The floats don't seem to be surprising, for small x you have sin(x)~x

So, sin(10^(-n-1/2)) is approximately 3.16227766/10^n

## unclear...

how do you get x1 and x2 ?

## unclear...

how do you get x1 and x2 ?

## Carl, do you see a way to keep root poin...

Carl, do you see a way to keep root point and tangent vector separate in the output? So that you really have <p>+t*<v> instead of <p+t*v>

## Carl, do you see a way to keep root poin...

Carl, do you see a way to keep root point and tangent vector separate in the output? So that you really have <p>+t*<v> instead of <p+t*v>

## @gkokovidis Here is the document mode mo...

@gkokovidis

Here is the document mode more appealing. He just needs to know when he is allowed to drop multiplication signs...

## @Mathematix  restart; ode1 := ...

restart; ode1 := L*(diff(i(t), t))+(R[1]+R[2])*i(t)+q(t)/C = 10*cos(8*t);

#now differentiate:

ode2 := diff(ode1, t);

ode2 := subs(diff(q(t), t) = i(t), ode2);

dsolve(eval({ode2, i(0) = 1, (D(i))(0) = 1}, [L = 4, R[1] = 8, R[2] = 6, C = 4]));

plot(rhs(%), t = 0 .. 2,y=0..1.2,gridlines=true);

solution has rationals and roots for coeffs, but should probably have integers. You may check the code.

## @Mathematix  restart; ode1 := ...

restart; ode1 := L*(diff(i(t), t))+(R[1]+R[2])*i(t)+q(t)/C = 10*cos(8*t);

#now differentiate:

ode2 := diff(ode1, t);

ode2 := subs(diff(q(t), t) = i(t), ode2);

dsolve(eval({ode2, i(0) = 1, (D(i))(0) = 1}, [L = 4, R[1] = 8, R[2] = 6, C = 4]));

plot(rhs(%), t = 0 .. 2,y=0..1.2,gridlines=true);

solution has rationals and roots for coeffs, but should probably have integers. You may check the code.

## Another way...

Interesting mapping, kitonum.

Her another way. The task would be to compute the intersection points.

http://en.wikipedia.org/wiki/Shoelace_formula

## Another way...

Interesting mapping, kitonum.

Her another way. The task would be to compute the intersection points.

http://en.wikipedia.org/wiki/Shoelace_formula

## floats...

you could insert
convert(simpledeq,rational); to remove the floats.

But the transform still ignores the given initial conditions. But more importantly, the  terms with square root are not transformed, I doubt there is an obvious way to do this.Even the direct way via dsolve yields no result, simpledeq is not so simple...

## floats...

you could insert
convert(simpledeq,rational); to remove the floats.

But the transform still ignores the given initial conditions. But more importantly, the  terms with square root are not transformed, I doubt there is an obvious way to do this.Even the direct way via dsolve yields no result, simpledeq is not so simple...

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