There are 1 questions in this calculation: for each question, the 1 derivative of t is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ cos(10t) - \frac{1}{10}sin(10t)\ with\ respect\ to\ t：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( cos(10t) - \frac{1}{10}sin(10t)\right)}{dt}\\=&-sin(10t)*10 - \frac{1}{10}cos(10t)*10\\=&-10sin(10t) - cos(10t)\\ \end{split}\end{equation} \]

Your problem has not been solved here? Please take a look at the  hot problems ！