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.
If it ain't broke, fix it until it is.
A number by itself is useful, but it is far more useful to know how accurate or certain that number is.
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)