Average growth rate = 4.2 cm/week.
So, common difference d = 4.2
<span>The height of the tree a0 = 200 centimeters.</span>
The height of the tree after end of the first week a₁ = 200 + 4.2 = 200 + 4.2(1)
The height of the tree after end of the second week a₂ = 200 + 4.2 + 4.2 = 200 + 4.2(2).
<span>The height of the tree after end of the third week a3 = 200 + 4.2 + 4.2 + 4.2 = 200 + 4.2(3).</span>
<span>The height of the tree after the end of the nth week an = 200 + 4.2(n).</span>
<span>The equation is <span>a_n</span><span></span><span> = 200 + 4.2(n)</span>.</span>