Answer:
The current that produces maximum power is 3A
Explanation:
Given
![P(c) = 20(c - 3)^2](https://img.qammunity.org/2022/formulas/mathematics/high-school/faq9auuziuak8onhrk6g3dzqqjg3my9jqm.png)
Required [Missing from the question]
The current that produces maximum power
First, we represent the function in standard form
![P(c) = 20(c - 3)^2](https://img.qammunity.org/2022/formulas/mathematics/high-school/faq9auuziuak8onhrk6g3dzqqjg3my9jqm.png)
![P(c) = 20(c - 3)(c - 3)](https://img.qammunity.org/2022/formulas/mathematics/high-school/qdlvpl0g7klm08eq1wri8uhsog9hb2hrpv.png)
Open bracket
![P(c) = 20(c^2 -6c+ 9)](https://img.qammunity.org/2022/formulas/mathematics/high-school/q04qwn87jup707ry6fsh5ck9tsxp8evq3l.png)
![P(c) = 20c^2 -120c+ 180](https://img.qammunity.org/2022/formulas/mathematics/high-school/4jzhwzmtxgfuqmp4jl0fymjeixac6r7fef.png)
The maximum value of c is:
![Max(c) = (-b)/(2a)](https://img.qammunity.org/2022/formulas/mathematics/high-school/cm81rfa77mb11oyuz41qxi1u4ovx2yqrxz.png)
Where:
![f(x) = ax^2 + b^2 + c](https://img.qammunity.org/2022/formulas/mathematics/high-school/xzooryeb0jwvnxktuheh41ifsixz61p22g.png)
By comparison:
![P(c) = 20c^2 -120c+ 180](https://img.qammunity.org/2022/formulas/mathematics/high-school/4jzhwzmtxgfuqmp4jl0fymjeixac6r7fef.png)
![a = 20](https://img.qammunity.org/2022/formulas/mathematics/high-school/we1wj7w4gmoa0g1zc8uhp60rwzg92c0wcj.png)
![b = -120](https://img.qammunity.org/2022/formulas/mathematics/high-school/c4cyxj4wjlb3p7p1e6grp2ymjypqqvsdu4.png)
![c = 180](https://img.qammunity.org/2022/formulas/mathematics/high-school/ydlpl74rdp1xkp435098t1sddvivccvatw.png)
So, we have:
![Max(c) = (-b)/(2a)](https://img.qammunity.org/2022/formulas/mathematics/high-school/cm81rfa77mb11oyuz41qxi1u4ovx2yqrxz.png)
![Max(c) = (-(-120))/(2 * 20)](https://img.qammunity.org/2022/formulas/mathematics/high-school/co6a3ggt7xl7omty05xflc0byxkqpjphlf.png)
![Max(c) = (120)/(40)](https://img.qammunity.org/2022/formulas/mathematics/high-school/2mba6idfrx3ipjiwuv8o5ypgnv5gdyovbm.png)
![Max(c) = 3](https://img.qammunity.org/2022/formulas/mathematics/high-school/ikvymlqy8orc9ju83dlvmn74l3ap5uu0b3.png)