int_{}^{}10^x dx = integrate it. if can show me the step please.
since your missing the ln(10) id find a suitable "1" to use on it
the value not needed. i just need the way to solve it. the notes given by my lecturer is incomplete.=(
10^x comes from a: 10^x but when we derivative it we get: 10^x ln(10) the ln(10) is just a constant so we can borrow it from a "1". ln(10)/ln(10) is a good "1" to use
its either that or fill you mind with all the u sub stuff for something so generic :)
u = 10^x du = 10^x ln(10) dx du/ln(10) = 10^x dx int: du/ln(10)
\[\int 10^x\ dx\] \[\int 1*10^x\ dx\] \[\int \frac{ln(10)}{ln(10)}*10^x\ dx\] \[\frac{1}{ln(10)}\int ln(10)*10^x\ dx\]
the 10^x dx need to sub it with dy/ln10 ?
need to? no. Can you? sure ...
then the final answer is??
\[\int 10^x\ dx\] \begin{array}l u=10^x\\ du=10^x\ ln(10)\ dx\\ \frac{1}{ln(10)}du=10^x\ dx \end{array} \[\int\frac{1}{ln(10)}du\] \[\frac{1}{ln(10)}\int\ du\]
the final answer is what you get to when you finish off the integration :)
is the final answer 1/ln(10) * 10^x ?
yep, sure is; +C if your doing the indefinite integral
ok... so if i did not sub the with the 1/ ln(10), would the answer still the same?
It must be the same.
there is only one answer ....
there are many methods to get there; but only one answer
ok...i understand it now.thanks a lot.=)
youre welcome
You can generalize this problem. It is true for all a > 0 that \[ \frac{d \ }{dx} a^x = \ln a \ . a^x \] Hence \[ \int a^x \ dx = \frac{1}{\ln a} a^x \ + C \]
Notice when a = e, than ln a = ln e = 1, hence \[ \int e^x = e^x + C \] which is what we expect.
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