Thread: logarithic

5= 3lnx - 1/2lnx

I assume you have to get both sides of the equation with the same term first. If I multiply by lnx, wouldn't it cancel out on the right side? The same for if I divide?

Originally Posted by startingover

5= 3lnx - 1/2lnx

I assume you have to get both sides of the equation with the same term first. If I multiply by lnx, wouldn't it cancel out on the right side? The same for if I divide?

Look at it this way:
Let y = ln(x)
Then:
5 = 3y - (1/2)y

5 = (5/2)y

y = 5*2/5 = 2

ln(x) = 2

x = e^2

-Dan

Hello, startingover!

Dan is absolutely correct.

5 .= .3·ln(x) - ½·ln(x)

Why are you trying to "cancel"?


We have: .3·ln(x) - ½·ln(x) .= .5

Combine: . . . . .(5/2)·ln(x) .= .5

Multiply by 2/5: . . . . ln(x) .= .2

Therefore: . . . . . . . . . . x .= .e²