Check my work: Arc Lengths
Derivative of x^3/3 + 1/4x^2 = x^2 -1/4x^2 Derivative squared:x^4 + 1/16x^4 -1/2
Derivative squared +1: x^4 + 1/16x^4 -1/2 + 1 = x^4 + 1/16x^4 +1/2 Square root: sqrt( x^4 + 1/16x^4 +1/2) = x^2 +1/4x^2 + 1/sqrt(2)
correct process.
\[\int\limits_{1}^{2} x^2 +1/4x^2 + 1/\sqrt(2) = 59/24+1/\sqrt(2)\]
answer is correct.
Problem is, the answer is just 59/24.
!!!
I don't see how I got that 1/sqrt(2) part wrong. My mathbook says it's just 59/24.
second part may be missing fm book. May be printing mistake.
@sirm3d , do you see what I did wrong?
i'm still checking.
Thanks!
\[\sqrt{x^4-\frac{1}{2}+\frac{1}{16x^4}+1}=\sqrt{x^4+\frac{1}{2}+\frac{1}{16x^4}}=x^2+\frac{1}{4x^2}\]
\[\Large L=\int_1^2 x^2+\frac{1}{4x^2} \;\mathrm dx\]
Okay, that makes sense. Thanks!
yw
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