0.04=0.08cos(12.57t)
arccos(0.04/0.08)/12.57=t
t=4.77
is this correct?
If yes, why the solution on the book is t=0.083?
Thanks in advance
$0.04=0.08\,\cos(12.57t)$
$\dfrac{0.04}{0.08}=\cos(12.57t)$
$\dfrac{1}{2}=\cos(12.57t)$
$\cos^{-1}\dfrac{1}{2}=(12.57t)$
$60\times\dfrac{\pi}{180}=(12.57t)$
$1.047=12.57t$
$t=0.083$