.
\n" );
document.write( "limit (((ln 2))^(x))/(cos ((pi)/4 sin (3 x))) as x \[LongRightArrow] - \[Infinity] = 0 ( T or F )
\n" );
document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~\r
\n" );
document.write( "
\n" );
document.write( "\n" );
document.write( "\r\n" );
document.write( "I placed (copy-pasted) the given expression into the Math editor, and this Math editor interpreted the expression this way\r\n" );
document.write( "\r\n" );
document.write( "
.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It is what I will use in my following analysis.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( " Step 1.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Consider a sequence of real numbers
,
,
, . . . ,
, . . . which approaches to
from the left.\r\n" );
document.write( "\r\n" );
document.write( "Then the sequence of real numbers
,
,
, . . . ,
, . . . approaches to
from the left.\r\n" );
document.write( "\r\n" );
document.write( "Then the sequence of real numbers
,
,
, . . . ,
approaches to
= 1/2 from the left.\r\n" );
document.write( "\r\n" );
document.write( "Then the sequence of real numbers
,
,
, . . . ,
, . . . \r\n" );
document.write( "\r\n" );
document.write( " approaches to
=
=
from the left.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Then the sequence of numbers
approaches to 0 (zero) from the right.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Thus for this sequence of numbers
, the numerator approaches to (ln(2))^(pi/18), which is some constant,\r\n" );
document.write( "\r\n" );
document.write( "while the denominator
approaches to zero.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Hence, as the argument x approaches to
from the left, \r\n" );
document.write( "the values of the given expression go to positive infinity.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "After that, as the argument x becomes greater than
, the expression takes finite values, again.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( " Step 2.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The function
in the denominator is periodical with the period
.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It means that the behavior of the given expression, which we detected in part (a), repeats inside each period [
,
],\r\n" );
document.write( "for all positive or negative integer numbers \"n\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "In other words, inside each such period, there is a converging sequence of real numbers, \r\n" );
document.write( "for which our expression goes to positive infinity, and after that the expression takes finite values, again.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( " Step 3.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It means that as x goes to plus or minus infinity, the given expression HAS NO limit.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "ANSWER. Of the two possible options, T or F, only F is valid.\r\n" );
document.write( "
\r
\n" );
document.write( "\n" );
document.write( "Solved.\r
\n" );
document.write( "
\n" );
document.write( "
\n" );
document.write( "\n" );
document.write( "========================\r
\n" );
document.write( "
\n" );
document.write( "
\n" );
document.write( "\n" );
document.write( "It can be solved in other way, too.\r
\n" );
document.write( "
\n" );
document.write( "\n" );
document.write( "\r\n" );
document.write( "In my solution above, I considered a sequence of numbers
, converging to pi/6 from the left,\r\n" );
document.write( "and shoved that for such sequence of arguments the whole function has positive values (going to + infinity).\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Similarly, if we consider another sequence of numbers
, converging to pi/6 from the right,\r\n" );
document.write( "we will get the sequence of the values of the whole function, which all are negative and go to - infinity.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Such a behavior repeats at each interval [
,
], for all positive or negative integer numbers \"n\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "But the function with such a behavior can not have limits as x goes to +infinity or -infinity.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "So, the given function has no limits as x goes to +infinity or -infinity.\r\n" );
document.write( "
\r
\n" );
document.write( "
\n" );
document.write( "\n" );
document.write( " \n" );
document.write( "