Integral Question
f(x)=\int_1^{3x^5} \ln(t^2+1) \, dt
\[f(x)=\int_1^{3x^5} \ln(t^2+1) \, dt\]like that?
is the question find the derivative?
yes it is,
how'd i guess?
too hard to integrate
use the chain rule. the derivative of the integral is the integrand, so replace t by \[3x^5\] and then multiply the answer by \[15x^4\]
yeah im having trouble with these. Ill try it sat!
\[f'(x)=\ln((3x^5)^2+1)\times 15x^4\]
i should have let you do it on your own, but once you see it you should realize how easy it is. it is clear what i did yes?
if you need a word of explanation let me know
i understand chain rule for ln (function within function). where did the 15x4 come from?
nvm 3x^5 derivative
15x^4 \ln(9x^{10}+1) ?
yes
it is the chain rule and you have a composite function. don't forget that \[F(x)=\int_a^x f(t)dt\] is a function of "x" so if you do not have an x in the upper limit, but rather something else, you have a composition like \[F(g(x))=\int_a^{g(x)}f(t)dt\] and so you need the chain rule
Join our real-time social learning platform and learn together with your friends!