Math Is Fun Forum

yonski

Member

Registered: 2005-12-14

Posts: 67

Logarithms

How do i calculate the value of y for which 2log(base3)y - log(base3)(y+4) = 2 ?

It's the log(y+4) bit that confuses me... i remember my teacher telling me what to do with those, and i remember thinking 'oh yeah, why didn't i think of that', but i've forgotten and i still can't think ofi it!

Thanks, Jon.

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Student: "What's a corollary?"
Lecturer: "What's a corollary? It's like when a theorem has a child. And names it corollary."

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: Logarithms

logarithms are only defined over the reals for positive values, so y = -3 is not valid, y = 12

even though y = -3 is fine for the second equation, it is not transferable to the first given that you are restricted to the reals i assume

Last edited by luca-deltodesco (2007-02-07 11:19:30)

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