You are not logged in.
Yes, indeed.
In the first post, that seems to have been done. Al-Allo reduced
L'Hopital's rule basically states that if
So you could differentiate the numerator and denominator until you no longer have 'z' in the denominator.
142956+7 = 142963 is prime
142956-7 = 142949 is prime
142758+1 = 142759 is prime
142758-1 = 142757 is prime
142164-5 = 142159 is prime
142164+5 = 142169 is prime
It could be useful to remember some trig identities or trig values. Though many of the common ones can be memorized through practice.
141966-5 = 141961 is prime
141966+5 = 141971 is prime
141768-1 = 141767 is prime
141768+1 = 141769 is prime
An example would help.