Ice-cream Posted June 7, 2005 Share Posted June 7, 2005 plz help me with this logartihm question: --- given that..... log xy = 2 log x + 2 determine the value of y for the following without using a calculator x = 3, 5, 10, 12 --- btw, i think the left side of the equation is actually: logx multiplied by y and not: log (xy) plz help!! Link to comment Share on other sites More sharing options...
DimShadow7 Posted June 7, 2005 Share Posted June 7, 2005 OK well if the left side is y * log x, then the formula simplifies to the following, log (x^y) = log (2x^2) --> 2 x^2 = x^y, therefore y = log(2 x^2)/ log(x) so for x =3 y = log 18 / log 3 5 --> log 50 / log 5 10 --> log 200 / log 10 12 --> log 288 / log 12 if it's the other way around and it is log (x y), then y = 2x 3 -> y = 6 5 -> y =10 10 -> y =20 12 -> y = 24 Link to comment Share on other sites More sharing options...
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