Odpowiedzi

2010-04-10T21:35:37+02:00
A) 1/x=1/a+1/b |*a wyznacz a i x
1/x*a=1+1/b |*x
a=1+1/b*x

1/x=1/a+1/b |*x
1=(1/a+1/b)*x |:(1/a+1/b)
x=1/(1/a+1/b)

B)E=RI+nrI/m |*m wyznacz I
Em=RI+nrI
Em=I(R+nr) |:(R+nr)
Em/(R+nr)=I
I=Em/(R+nr)

C) 1/R=1/R1+1/R2+1/R3 |*R3 wyznacz R
R2=R2+R+1
R2-R2-R=1
-R=1 |*(-1)
R=-1

D 2a-x/5+a-3x=4x+2a/2 |*2 wyznacz x i a
4a-2x/5+2a-6x=8x+2a
4a+2a-2a=8x+2x/5+6x
4a=14x+2x/5 |:4
a=3,5x+2x/20
a=3,5x+x/10

2a-x/5+a-3x=4x+2a/2 |*5
10a-x+5a-15x=20x+10a/2
-x-15x-20x=10a/2-10a-5a
-36x=5a-15a
-36x=-10a |*(-36)
x=10/36a
x=5/18 a
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