Question

Can someone clarify this calc problem on arc length? Calc

Answer 1

I Understand everything until the very last line… Where did the "ln" come from?

Answer 2

??

Answer 3

i dont find anything useful in the attached snapshot... check it once ?

Answer 4

ooops im so sorry i attached the wrong pic! here it is!

Answer 5

love @zepdrix pix though...

Answer 6

whut? XD

Answer 7

\[\large b^{\log_b(x)}=x\]

Answer 8

just something you best memorize
\[\int \sec(x)dx=\ln(\sec(x)+\tan(x))\]

Answer 9

integrating secant comes along very often, especially in a trig sub