Please answer quickly Given: sin(A) = 4/5, pi/2 < A < pi and sin(B) = -2root5/5, pi < B < 3pi/2 What is the value of cos(A – B)?

-√5/5

Step-by-step explanation:

Given the following

sin(A) = 4/5

sinB - -2√5/5

SinA = 4/5 = opp/hyp

We can get cosA

opposite = 4

hypotenuse = 5

Adj = √5²-4² (pythagoras theorem)

Adj = √25-16

Adj = √9

Adj = 3

Cos A = Adj/hyp

Cos A = 3/5

Also

Sin B = -2√5/5 = opp/hyp

opposite = -2√5

hypotenuse = 5

Adj = √5²-(2√5)² (pythagoras theorem)

Adj = √25-20

Adj = √5

Cos B = Adj/hyp

Cos B =  √5/5

Evaluate cos (A-B)

cos (A-B) = cosAcosB + sinAsinB

cos (A-B) = 3/5(√5/5)+4/5(-2√5/5)

cos (A-B)  = 3√5/25 - 8√5/25

cos (A-B) = -5√5/25

cos (A-B) = -√5/5

Hence the value of cos (A-B) is -√5/5

the answer to this question is in the pic

answer:

the position of equilibrium will shift to the left.

step-by-step explanation:

the general equation for the dissociation of a weak base is

b + h₂o   ⇌   bh⁺ + oh⁻

according to le châtelier's principle, when a stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

if you apply a stress by adding more bh⁺ or oh⁻,   the system will respond by moving in a direction that gets rid of the added ions.

the position of equilibrium will shift to the left, forming more of the undissociated base.