Question: error that I don't know how to fix

Hi I attempted to plot this but failed... my instructor gave us a list of functions according to our name and when I put them together into an equation to plot I kept getting an error. I included the function list at the bottom. I am using DEtools:

Loading Student:-Calculus1

with(DEtools):

#tangent field for dy/dx = AB + CD where A -first letter of my name, B - second letter of my first name, C - first letter of my surname, D- second letter of my surname, which in my case (Tran Lam) gives using the Name-function list; t=y^(2) +5 y, r= 3(x^(2) +y^(2)),l=x^(1/(3)), a= sin(xy), dy/dx = (sin (xy) +(3 x^(2)+x^(1/(3))+4 y^(2)+5 y))

dfieldplot(diff(y(x), x) = sin(xy)+3*x^2+x^(1/3)+4*y^2+5*y, y(x), x = -5 .. 5, y = -5 .. 5, title = `tangent field`, color = black);
%;Warning, y is present as both a dependent variable and a name. Inconsistent specification of the dependent variable is deprecated, and it is assumed that the name is being used in place of the dependent variable.Error, (in DEtools/dfieldplot) extra unknowns found: xy

 dfieldplot(diff(y(x), x) = sin(xy)+3*x^2+x^(1/3)+4*y^2+5*y, y(x), x = -5 .. 5, y = -5 .. 5, title = `tangent field`, color = black);

Warning, y is present as both a dependent variable and a name. Inconsistent specification of the dependent variable is deprecated, and it is assumed that the name is being used in place of the dependent variable.Error, (in DEtools/dfieldplot) extra unknowns found: xy

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In case the function list is needed. I don't know why there are two different functions for m and n but in my case I don't use them so it doesn't matter.

Letter                                      Function                      Letter                          Function

a                                              sin(xy)                          m                                 xy

b                                              x³ +y                            n                                  sin(3x-y)

c                                              2x-3y                           o                                  cos(x+y)

d                                              x² +cos(y)                    p                                  y³

e                                              x⁴- 2sin(x+y)                q                                  sin(x²-2y)

f                                               5                                  r                                   3(x² +y²)

g                                              -7y²                              s                                  cos(x) – sin(4y)

h                                              sin(x² –x)                      t                                   y² +5y             

i                                               - 15cos(2xy²)               u                                  -4x³y

j                                               sin(y² –x²)                     v                                  -3xy³               

k                                              2y – sin(y)                    w                                  x + y^1/3

l                                               x^1/3                               x                                  2y + x

m                                             x+ y sin(x)                    y                                  x cos(y)- y²

n                                              xy – cos(x)                   z                                   y² – cos(y)