helpppp as, gs

a).  Substitute 1 and 2 into the expression for R(n) to get two simultaneous equations for h and k:

n = 1:       h^1/2/k = 4.8           (working on millions of dollars)

n = 2:       h¹/k  = 5.76  from this we have h = 5.76k.  Put this into the first expression above to get:

(5.76k)^1/2/k = 4.8    or 5.76^1/2/k^1/2 = 4.8.   Multiply both sides by k^1/2 and divide both sides by 4.8 to get:

k^1/2 = 5.76^1/2/4.8.   Square both sides:  k = 5.76/4.8²

$${\mathtt{k}} = {\frac{{\mathtt{5.76}}}{{{\mathtt{4.8}}}^{{\mathtt{2}}}}} \Rightarrow {\mathtt{k}} = {\mathtt{0.25}}$$

Hence from the n = 2: equation above we have h = 5.76*0.25 or 

$${\mathtt{h}} = {\mathtt{5.76}}{\mathtt{\,\times\,}}{\mathtt{0.25}} \Rightarrow {\mathtt{h}} = {\mathtt{1.44}}$$

Remember that the result of using these values in R(n) = h^n/2/k will be in millions of dollars.

For the sum of R(n) to n, notice that it can be written as:

sum(n) = (a + a² + a³ + ... + aⁿ)/k  where a = h^1/2

The numerator is a geometric progression giving the result of sum(n) = a*(aⁿ-1)/[(a-1)k] 

or sum(n) = (h^1/2)*(h^n/2-1)/[(h^1/2-1)k}

See if you can now have a go at part b).

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