Saturday, June 7, 2014

Differentiate f(x) = sinx * lnx

f(x) = sinx* lnx


To find the
first derivative, we will use the product rule:


Let f(x) =
u*v   such that:


u= sinx   ==>   u' =
cosx


v= lnx  ==>   v' =
1/x



Now we know
that:


if f(x) = u*v    


Them
f'(x) = u'v + uv'


==> f'(x) =  cosx*lnx + sinx*
1/x


==> f'(x) = cosx*lnx +
sinx/x


               =
(x*cosx*lnx + sinx )/x

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