TeX source:

\frac{\mathbf{d} \mathrm{T}}{\mathbf{d} \mathbf{t}}=\frac{(1+\mathrm{t}+\sin (\mathrm{t})) \cdot \mathbf{D}(72)-72 \cdot \mathbf{D}(1+\mathrm{t}+\sin (\mathrm{t}))}{(1+\mathrm{t}+\sin (\mathrm{t}))^{2}}=\frac{-72(1+\cos (\mathrm{t}))}{(1+\mathrm{t}+\sin (\mathrm{t}))^{2}}