Reiszing figure to occupy entire frame

[fishbackp]

I have a frame within my root window and wish to place a plot inside the frame. What I have so far is the following:

from tkinter import Tk,Frame,TOP,BOTH
from matplotlib import pyplot as plt
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
import numpy as np

plt.rcParams["figure.figsize"] = [18,10]

root=Tk()
root.wm_title("Root Window")
root.geometry('1500x1000') 

x = np.linspace(0, 2 * np.pi, 400)
y = np.sin(x ** 2)
fig, ax = plt.subplots()
ax.plot(x, y)

canvas_frame=Frame(root,bg='yellow')
canvas_frame.pack(side=TOP,expand=True)
canvas = FigureCanvasTkAgg(fig, master=canvas_frame)

canvas.get_tk_widget().pack(side=TOP,fill=BOTH,expand=True)
canvas.draw()

root.mainloop()

The problem I have is that I want to increase the plot size so it occupies the entire frame. I'm unsure why adjusting plt.rcParams doesn't do what I need.