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.
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)