What is f(x) = int 1/x f(x)=∫1x if f(2)=1 f(2)=1?
1 Answer
May 3, 2016
Explanation:
The derivative of
lnx=1/x lnx=1x hence the anti-derivative of
1/x" is"lnx1x islnx
rArrF(x)= int1/x dx=lnx+c⇒F(x)=∫1xdx=lnx+c To find c , use f(2) = 1
ln2 + c = 1 → c = 1 - ln2
rArr F(x)=lnx+1-ln2⇒F(x)=lnx+1−ln2 using
• lnx-lny=ln(x/y)"to simplify"∙lnx−lny=ln(xy)to simplify
rArr int1/x dx= ln(x/2)+1⇒∫1xdx=ln(x2)+1