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2010-02-15T22:51:10+01:00
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dane:r=2cm = 0,02m, x=1m=100cm,
szukane: y
1/f = 1/x + 1/y f = r/2 1/f = 2/r
2/r = 1/x + 1/y
1/y = 2/r - 1/x = [2x - r]/xr
y = xr/[2x - r] = 2cm*100cm/198cm = 1,01cm

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