style: use simpler syntax express polynomials

Co-authored-by: appgurueu <34514239+appgurueu@users.noreply.github.com>

Author: vil02

Maths/test/BisectionMethod.test.js

@@ -1,14 +1,7 @@
 import { findRoot } from '../BisectionMethod'
 
 test('Equation f(x) = x^2 - 3*x + 2 = 0, has root x = 1 in [a, b] = [0, 1.5]', () => {
-  const root = findRoot(
-    0,
-    1.5,
-    (x) => {
-      return Math.pow(x, 2) - 3 * x + 2
-    },
-    8
-  )
+  const root = findRoot(0, 1.5, (x) => x ** 2 - 3 * x + 2, 8)
   expect(root).toBe(0.9990234375)
 })
 
@@ -37,26 +30,10 @@ test('Equation f(x) = sqrt(x) + e^(2*x) - 8*x = 0, has root x = 0.93945851 in [a
 })
 
 test('Equation f(x) = x^3 = 0, has root x = 0.0 in [a, b] = [-1.0, 1.0]', () => {
-  const root = findRoot(
-    -1.0,
-    1.0,
-    (x) => {
-      return Math.pow(x, 3)
-    },
-    32
-  )
+  const root = findRoot(-1.0, 1.0, (x) => x ** 3, 32)
   expect(root).toBeCloseTo(0.0, 5)
 })
 
 test('Throws an error when function does not change sign', () => {
-  expect(() =>
-    findRoot(
-      -1.0,
-      1.0,
-      (x) => {
-        return Math.pow(x, 2)
-      },
-      10
-    )
-  ).toThrowError()
+  expect(() => findRoot(-1.0, 1.0, (x) => x ** 2, 10)).toThrowError()
 })