Question

a to the power minus 1 + b to the power minus 1 ÷ a to the power minus 2 - b to the power minus 2​

Answer 1

Answer:

Step-by-step explanation:

=(1/a+1/b)/(1/a² - 1/b²)

=(1/a+ 1/b)/ (1/a +1/b)(1/a - 1/b)  [a² -b²=(a-b)(a+b)]

=1/(1/a - 1/b)

=1/b-a/ab

=ab/b-a

Answer 2

Answer:

Here is your answer

Step-by-step explanation:

Proof: P(A − B) = P(A) − P(B)

let X ∈ P(A-B) ⇒ X ∈ A and X ∉ B ⇒ X ∈ P(A) and X ∉ P(B) ⇒ X ∈ P(A) - P(B)

let X ∈ P(A) - P(B) ⇒ X ∈ P(A) and X ∉ P(B) ⇒ X ∈ A and X ∉ B ⇒ X ∈ (A - B) ⇒ X ∈ P(A - B)

so we have P(A − B) = P(A) − P(B)