admin

16 Questions
1410 Answers

+4

2311

1

+3146

Neue Datenschutzrichtlinie, Mai 2018

Hallo,

Diese Webseite wurde aktualisiert mit kleineren Anpassungen an die DS-GVO.
прочитайте больше ..

Не по теме

admin 27 мая 2018 г.

+19

3475

2

+3146

New Privacy Policy, May 2018

Hello,

this website was updated today because of some legal changes here in Europe. ("GDPR").
прочитайте больше ..

Не по теме

admin 27 мая 2018 г.

+6

2267

1

+3146

New version is online for two weeks now, any problems?

Hi,

Any problems? You can use the "Report a Problem" link in the footer, or send me an email to britnex+bugs@gmail.com
прочитайте больше ..

admin 12 сент. 2015 г.

+20

2713

16

+3146

New website is online.

Hi,

Any problems? You can use the "Report a Problem" link in the footer, or send me an email to britnex+bugs@gmail.com , thank you!
прочитайте больше ..

Melody ●●●●●●●●●●●●●●●●

admin 30 авг. 2015 г.

+7

2569

2

+3146

Neue Version der Webseite ist online

Hi,

Probleme bitte per Email an britnex+bugs@gmail.com melden, Danke!
прочитайте больше ..

admin 30 авг. 2015 г.

+67

3

4473

11

+3146

three times ten to the power of negative 2

help what is 3x10to the power of negative 2

●●●●●●●●●●●

admin 26 янв. 2012 г.

+3146

0

[input](-9)(-8)/(-2)[/input]

admin19 февр. 2012 г.

+3146

0

[input]4=(5x-5)/(7x)-(6x^2-50x+16)/(7x)[/input]

4=((5x-5)-(6x^2-50x+16))/(7x)
4=(5x-5-6x^2+50x-16)/(7x)
4=(-6x^2+55x-21)/(7x)
28x=-6x^2+55x-21
28x-55x= -6x^2-21
-27x = -6x^2-21
-6x^2+27x-21=0
-6*(x^2-27x/6+21/6)=0

-6*(x^2-27x/6+21/6) is zero, if (x^2-27x/6+21/6) is zero:

x _1,2 = -p/2 +- sqrt( (p/2)^2 - q )
p = -27/6
q = 21/6
x1 = -(-27/6)/2 + sqrt( ((-27/6)/2)^2 - 21/6 )
[input]-(-27/6)/2 + sqrt( ((-27/6)/2)^2 - 21/6 )[/input]
x1 = 3.5 = 7/2

x2 = -(-27/6)/2 - sqrt( ((-27/6)/2)^2 - 21/6 )
[input]-(-27/6)/2 - sqrt( ((-27/6)/2)^2 - 21/6 )[/input]
x2 = 1

admin19 февр. 2012 г.

+3146

0

[input]100+19%[/input]
[input]100-19%[/input]
[input]100*19%[/input]

admin19 февр. 2012 г.

+3146

0

2x+3y=1

-6x-9y=-1 | /-2
2x+3y=1/2

1=2x+3y=1/2
false

[input]solve( 2x+3y=1, -6x-9y=-1 )[/input]

admin18 февр. 2012 г.

+3146

0

[input]798*(1+0.031/4)^(21*4)[/input]

admin18 февр. 2012 г.

+3146

0

[input]-6(2y+3)+6=-12[/input]

admin18 февр. 2012 г.

+3146

0

[input]2/1-2/3[/input]

admin18 февр. 2012 г.

+3146

0

m^2 + 8m + 3 =0
m^2 + 8m = -3

m^2 + 8m + 16 = -3 + 16
(m + 4)^2 + 16 = -3+16
(m + 4)^2 = -3+16
(m + 4)^2 = 13

(m + 4) = ±sqrt(13)
m = ±sqrt(13) - 4

m ₁ = -sqrt(13) - 4
m ₂ = sqrt(13) - 4

[input]x^2 + 8x + 3 =0[/input]

admin18 февр. 2012 г.

+3146

0

isaac3211:
y''+y'-6y=e^(-3x)?

first the complementary solution for: y''+y'-6y=0
y(x)=e^(λ*x)

e^(λ*x) d^2/dx^2 + e^(λ*x) d/dx - 6*e^(λ*x) = 0

substitute:
e^(λ*x) d^2/dx^2 with λ^2*e^(λ*x)
e^(λ*x) d/dx with λ*e^(λ*x)

λ^2*e^(λ*x)+λ*e^(λ*x)-6*e^(λ*x) = 0

(λ^2+λ-6)*e^(λ*x) = 0
solve:
λ^2+λ-6=0
λ=-3 and λ=2

so:
y1(x) = c1*e^(-3*x)
y2(x) = c2*e^(2*x)
(c1,c2 = constant)
=> the complementary solution y(x):
y(x) = y1(x)+y2(x) = c1*e^(-3*x) + c2*e^(2*x)

[input]diff(diff(y(x),x),x)+diff(y(x),x)-6*y(x)=0[/input]

ok, looks good. now to the particular solution: y''+y'-6y=e^(-3x)
yp(x) = x*a1*e^(-3x)

yp(x) d/dx = a1*e^(-3x)*-3*a1*e^(-3x)*x
[input]diff( x*a1*e^(-3x), x)[/input]

yp(x) d^2/dx^2 = a1*( -6*e^(-3x)+9*e^(-3x)*x )
[input]diff(diff( x*a1*e^(-3x), x),x)[/input]

now insert both diff'd yp(x) and yp(x) into y''+y'-6y=e^(-3x)
a1*( -6*e^(-3x)+9*e^(-3x)*x ) + a1*e^(-3x)*-3*a1*e^(-3x)*x - 6*x*a1*e^(-3x) = e^(-3x)
-5*a1*e^(-3x) = e^(-3x)
a1 = -1/5
yp(x) = -(1/5)*e^(-3x)*x

y(x) = c1*e^(-3*x) + c2*e^(2*x) + y(p)
y(x) = c1*e^(-3x) + c2*e^(2x) - (1/5)*e^(-3x)*x

admin18 февр. 2012 г.

+3146

0

[input]5(4^x)=6[/input]

admin17 февр. 2012 г.