I have a probelm with this:
if log(3)= x and log(5)= y, then log(45√15) =...??
I tried this: log(45)+log(√15) = log(3).(3).(5)+½log(3).(5)
and that's all equal to.. x+x+y+½(x+y) = 2x+y+½(x+y) = 2x√x+y√y
but the real answer is ½(5x+2y)
anyone can help me? please..I really confuse...
Last edited by Dyoni (2013-05-12 16:20:35)
Which does not agree with your real answer...
Please check your "real answer," because when an answer does not agree with what I get it is almost certainly wrong. Okay, that is an exaggeration, it has a darn good chance of being wrong. Okay, that is stretching it too but check it anyway.
In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.
Try wolfram to check that.
Enter "PowerExpand[log(45 sqrt(15))]" the substitutions will verify Bobby's answer.
Last edited by ElainaVW (2013-05-12 17:48:30)