since through the first hints, f(x) is continuous at x=0, I know that b=0, and from the second hint that derivative of f(0) is also equal to 0 so is that a and b equal to 0, but it seems that not correct.
f(x) will be continuous if the each of the individual parts is continuous and the value of those parts agree at 0each part is composed of continuous functions so we just have to check values at 0f(0−)=atan−1(0)+b=bf(0+)=limx→0 ln(1+sin(x))xUsing L'Hopital's rule we take the derivatives of numerator and denominator and look at the ratioddxln(1+sin(x))=cos(x)1+sin(x)|x=0=1ddx=1 and thus the limit is f(0+)=limx→0 ln(1+sin(x))x=11=1and thus b=1
The value of the derivative at 0 must also agree from both sidesI'm going to let you work this bit outTake the derivatives of both terms of f(x) one can be immediately evaluated at 0, the other you'll have to take the limit as x→0set the value a such that the two values agree
.hello , bro,
May know why you do derivative for ln(1+sinx)/x but ignore the derivative for atan^-1x+b???
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“I’m going to let you work this bit out …”
Rom peeled and predigested the first banana for you. You are a big monkey now, so you need to learn how to peel and eat bananas on your own volition. Otherwise, you will never grow up to be big and smart. (Not that there is much hope for the smart part.)
GA