a. Show for the upper-tailed test with 1 and 2 known that as either m or n

Question:

a. Show for the upper-tailed test with σ1 and σ2 known that as either m or n increases, b decreases when µ1 = µ2. Δ0.
b. For the case of equal sample sizes (m = n) and fixed a, what happens to the necessary sample size n as β is decreased, where β is the desired type II error probability at a fixed alternative?