HELP PLEASE BRAINLIEST I NEED HELP AND FAST

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

(a) (8%) compute the probability of an even integer among the 100 integers 1! , 2! , 3! , until 100! (here n! is n factorial or n*(n-1)*(n-2) *… 1) (b) (16%) compute the probability of an even integer among the 100 integers: 1, 1+2, 1+2+3, 1+2+3+4, …., 1+2+3+… + 99, and 1+2+3+… + 100

What is not true about kl and mn? what is mn? (show )