求方程为 $y=3x^3\ln x^4$ 的曲线的驻点的精确坐标，其中 $x>0$。

Answer all questions. You should use a calculator where appropriate.

You must show all necessary working clearly; no marks will be given for unsupported answers from a calculator.

Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place for angles in degrees, unless a different level of accuracy is specified in the question.

请回答所有题目。适当时应使用计算器。必须清楚展示所有必要的计算过程；仅给出计算器答案而没有过程，不予评分。除非题目另有精度要求，非精确数值答案保留 3 位有效数字，以度为单位的角度保留 1 位小数。

因 $x>0$，先把 $\ln(x^4)$ 写成 $4\ln x$。乘积求导后令导数为零，并代回求纵坐标。

For $x>0$, $\ln(x^4)=4\ln x$, so $y=12x^3\ln x$.

Differentiating,

Since $x>0$, a stationary point requires

Substituting,

The stationary point is