Exercise 5.3 equilibrium of demand and supply

[tpemartin]

Exercise 5.3 It is very common that economic model has some equilibrium condition as the intersection of two straight lines, like demand and supply. They can be expressed as: demand: p_d(q)=a+bq supply: p_s(q)=c+dq In equilibrium, (p, q) satisfies p_d(q)=p_s(q) and p=p_d(q)=p_s(q*).

If you solve for $q$ and $p$, q=(a-c)/(d-b) p=a+bq*.

1. Run the following code and solve for equilibrium and save it in a list with two element names q_star and p_star. Each has its value in corresponding to q and p that your program solved.

   a=1; b=-3; c=0; d=1

2. Create a function called solve_equilibrium so that the following code would work:

   
   a=1; b=-3; c=0; d=1
   equilibrium1 <- solve_equilibrium()
   print(equilibrium1)

a=2; b=-3; c=0; d=1 equilibrium2 <- solve_equilibrium() print(equilibrium2)

a=1; b=-3; c=0; d=1.5 equilibrium3 <- solve_equilibrium() print(equilibrium3)

[raychiu135]

https://github.com/raychiu135/110-1-r4ds-main/blob/742de34e4f1aab7edeab1f5700fb6a80f8b5c8bf/exercise_5.3.rmd#L2

[tpemartin]

@raychiu135

1. 'Error: object 'q_star' not found'. The element value of p_star need a name call on q_star but q_star object is not in the global environment.

[raychiu135]

https://github.com/raychiu135/110-1-r4ds-main/blob/895ad0f4b7756af41d58d95e2f15cf31de36018c/exercise_5.3.rmd#L2

[linttttt]

https://github.com/linttttt/110-1-r4ds-main/blob/9174628cb663da6629080d65931afe76224c50e6/studyCH5(EX).Rmd#L102