Линейные уравнения

levelp · May 23, 2015 · 74f43e6 · 74f43e6
1 parent 484d1ef
commit 74f43e6
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diff --git a/src/main/java/QuadraticEquation.java b/src/main/java/QuadraticEquation.java
@@ -13,6 +13,9 @@ public class QuadraticEquation {
      * @return корни уравнения (значения x)
      */
     public static double[] solve(double a, double b, double c) {
+        if (Math.abs(a) < EPS) {
+            return new double[]{-c / b};
+        }
         // Дискриминант
         double D = Math.pow(b, 2) - 4 * a * c;
         if (Math.abs(D) < EPS)

diff --git a/src/test/java/QuadraticEquationTest.java b/src/test/java/QuadraticEquationTest.java
@@ -43,4 +43,13 @@ public void testOneRootAccuracy() {
     public void testNoRoots() {
         assertArrayEquals("x^2 + 2 = 0", new double[]{}, QuadraticEquation.solve(1, 0, 2), EPS);
     }
+
+    /**
+     * Линейное уравнение
+     */
+    @Test
+    public void testLinear() {
+        assertArrayEquals("3x + 4 = 0", new double[]{-4 / 3.}, QuadraticEquation.solve(0, 3, 4), EPS);
+        assertArrayEquals("1e-16*x^2 + x - 100 = 0", new double[]{100}, QuadraticEquation.solve(1e-16, 1, -100), EPS);
+    }
 }