hello guys it had been long since last login of mine.
derivative problem again......
Find f'(x) for f(x)=3xlnx√(lnx)(x√3−1)2xsinxcotx
That's really a complicated one......
I will give it a go.
f(x)=3xlnx√(lnx)(x√3−1)2xsinxcotx=(32)x(lnx√(lnx)(x√3−1)cosx)
=(32)x(lnxcosx)(√(lnx)(x√3−1))
There we seperate it into 3 parts!!
Part 1 = (3/2)^x
Part 2 = (ln x)/(cos x)
Part 3 = sqrt((ln x)(x^(sqrt 3 - 1)))
Next we will find the derivative of (3/2)^x using implicit differentiation......
y=(32)xlny=xln321ydydx=ln32dydx=yln32=(32)x(ln32)
Then we find the derivative of ln x/ cos x......
(lnxcosx)′=(1x)(cosx)−(−sinx)(lnx)cos2x=cosxx+sinxlnxcos2x=1xcosx+tanxlnxcosx=1+xtanxlnxxcosx
Then we came to the most complicated part: derivative of sqrt((ln x)(x^(sqrt 3 - 1)))
(√(lnx)(x√3−1))′y=√uu=(lnx)(x√3−1)y′=(x√3−2)+((√3−1)(lnx)(x√3−2))2√lnx(x√3−1)
Next we apply the product rule to Part 1 and Part 2 and call it Part 1,2
(Part 1 times Part 2)'
= Part 1 ' Part 2 + Part 2 ' Part 1
= ((32)xln32)(lnxcosx)+(1+xtanxlnxxcosx)(32)x
= (3xlnxln3−3xlnxln22xcosx)+(3x+3x⋅xtanxlnx2xxcosx)
=3x(xlnxln3−xlnxln2+1+xtanxlnx)2xxcosx
I will name this fraction y.
Then we find the derivative of Part1,2:
3xlnx(xlnxln3−xlnxln2+1+xtanxlnx)+3x(lnxln3+ln3−lnxln2−ln2+tanxlnx+xsec2xlnx+tanx)22xx2cos2xOops it's too long :( I will name this looooooonnnnnggggg fraction z then)
Then we use product rule for Part1,2 and Part 3:
f'(x)= y(x√3−2+(√3−1)(lnx)(x√3−2)2√lnx(x√3−1))+z(√lnx(x√3−1))