Sin J: 5/13, 0.38
cos J: 12/13, 0.92
tan J: 5/12, 0.42
sin K: 12/13, 0.92
cos K: 5/13, 0.38
tan K: 12/5, 2.40
N+14=17. n=3. So the missing number is 3.
add 4 each time
the nth term is a_n or f(n)
the next term after that is a_{n+1} or f(n+1)
so each term is 4 more than previous
basically
a_{n+1}=4+a_n or
f(n+1)=4+f(n)
same thing