Fix x_range slicing in get_area_under_graph to prevent TypeError

[mathsvisualization]

Motivation

Fix a bug in get_area_under_graph where passing the full graph.x_range
to inverse_interpolate could cause a TypeError:

TypeError: inverse_interpolate() takes 3 positional arguments but 4 were given

This happened when graph.x_range had more than 2 elements. Slicing the
x_range ensures that alpha bounds are calculated correctly and subgraphs
are created reliably.

Proposed changes

• Slice graph.x_range to only the first two elements when passing to inverse_interpolate: graph.x_range[:2].
• Preserve existing behavior for standard 2-element x_range.

Test

Code:

from manimlib import *

class HelloWorldExample(InteractiveScene):
    def construct(self):
        # Setup
        plane = NumberPlane(
            x_range=(-4, 4), y_range=(0, 1.5, 0.5),
            width=14, height=5,
            background_line_style=dict(
                stroke_color=GREY_B,
                stroke_width=2,
                stroke_opacity=0.75
            )
        )
        plane.to_edge(DOWN)
        plane.x_axis.add_numbers(num_decimal_places=1, excluding=[0])
        plane.y_axis.add_numbers(font_size=24)
        self.add(plane)

        # graph
        graph = plane.get_graph(lambda x: np.exp(-x**2))
        graph.set_stroke(BLUE, 2)
        self.add(graph)

        area = plane.get_area_under_graph(graph, x_range=[-1, 1])
        area.scale(0.7)
        area.next_to(graph.pfp(0.65), UR)
        self.add(area)

Result:

• No TypeError occurs
• Area under the graph is filled correctly for both standard and extended x_ranges

Before:

After: