df（x）=
                      $$2.x\mathrm{余弦}\left(x^{2.}\right)$$

Df2=
                      $$4.\mathrm{余弦}\left(4.\right)$$

ans=-2.6146

Df=
                      $$T^{2.}\mathrm{余弦}\left(T^{2.}x\right)$$

var =
                      $$x$$

Df=
                      $$2.Tx\mathrm{余弦}\left(T^{2.}x\right)$$

D4=
                      $$360.T^{2.}$$

D5=
                      $$720T$$

D6=
                      $$720$$

Df=
                      $$-x^{3.}\mathrm{余弦}\left(xY\right)$$

Df=
                      $$0$$

Df=
                      $$1.$$

Df=
                      $$2.x\mathrm{余弦}\left(xY\right)-x^{2.}Y罪\left(xY\right)$$

Df=
                      $$x^{2.}{Y}^{3.}罪\left(xY\right)-6.x{Y}^{2.}\mathrm{余弦}\left(xY\right)-6.Y罪\left(xY\right)$$

dy =

                      

                       $$2.F\left(x\right)\frac{\partial }{\partial x}\mathrm{}F\left(x\right)$$
                     

Dy2=

                      

                       $$2.\frac{\partial }{\partial x}\mathrm{}F\left(x\right)$$
                     

Dy3=
                      $$2.F\left(x\right)$$

L=

                      

                       $$\frac{M{\left(\frac{\partial }{\partial T}\mathrm{}x\left(T\right)\right)}^{2.}}{2.}-\frac{K{x\left(T\right)}^{2.}}{2.}$$
                     

D1=

                      

                       $$M\frac{\partial }{\partial T}\mathrm{}x\left(T\right)$$
                     

D2（t）=
                      $$-Kx\left(T\right)$$

ans（t）=

                      

                       $$M\frac{{\partial }^{2.}}{\partial T^{2.}}\mathrm{}x\left(T\right)+Kx\left(T\right)=0$$
                     

阿尔法=
                      $$Y^{\mathrm{T}}\mathrm{A.}x$$

Dx=
                      $$Y^{\mathrm{T}}\mathrm{A.}$$

dy =
                      $$x^{\mathrm{T}}{\mathrm{A.}}^{\mathrm{T}}$$

y =
                      $$X^{\mathrm{T}}\mathrm{A.}X$$

d =
                      $$X^{\mathrm{T}}\otimes X$$

ans=1×23 3.