Q$2.(65$ points$)$ Show your work as done in class. Clearly write the summation and its closed form.

$($See cheat sheet for summations. E$.$g$.=,$ has closed form: $.)$

a$)(5$ points$)$

Assume that void mistery$($int X$)$; has time complexity O$($X$)$

Fill in the time complexity of the function call: mistery$(18)$;

TCmistery$(18)=$ O$(1)$

b$)(10$ points$)$

for$($k $=1$; k $<=$ W; k$=6*$k$)$

for$($j $=0$; j $<$ S; j$++)$

printf$("$D$")$;