diff --git a/FusionCalculator b/FusionCalculator
index 43d3864..d831063 160000
--- a/FusionCalculator
+++ b/FusionCalculator
@@ -1 +1 @@
-Subproject commit 43d38645a527aff10f585a01f62313cbd840014e
+Subproject commit d83106358fbf7293a112d6f3c75f6113e546aa09
diff --git a/SharpCalculator.Tests/ComplicatedExpressionTests.cs b/SharpCalculator.Tests/ComplicatedExpressionTests.cs
index bd9b411..52a9306 100644
--- a/SharpCalculator.Tests/ComplicatedExpressionTests.cs
+++ b/SharpCalculator.Tests/ComplicatedExpressionTests.cs
@@ -15,15 +15,21 @@ public class ComplicatedExpressionTests
     [Theory]
     [InlineData(0.9,2,3)]
     public void Expression2(double a, double b, double c) => 
-        Assert.Equal( Math.Sin(a)-b*Math.Cos(c), Calculator.Calculate($"sin(({a}))-(({b})*cos(({c})))"));
+        Assert.Equal( Math.Sin(a)-b*Math.Cos(c), 
+            Calculator.Calculate($"sin(({a}))-(({b})*cos(({c})))"), 
+            FunctionTests.PRECISION);
 
     [Theory]
     [InlineData(0.9,2,3)]
     public void Expression3(double a, double b, double c) => 
-        Assert.Equal( a*Math.Pow(b,c)+a*Math.Pow(b,c+1)+a*Math.Pow(b,c+2), Calculator.Calculate($"({a})*({b})^({c}) + ({a})*({b})^({c+1}) + ({a})*({b})^({c+2})"));
+        Assert.Equal( a*Math.Pow(b,c)+a*Math.Pow(b,c+1)+a*Math.Pow(b,c+2), 
+            Calculator.Calculate($"({a})*({b})^({c}) + ({a})*({b})^({c+1}) + ({a})*({b})^({c+2})"), 
+            FunctionTests.PRECISION);
 
     [Theory]
     [InlineData(0.9,2,3)]
     public void Expression4(double a, double b, double c) => 
-        Assert.Equal(a/(b+Math.Tan(c)), Calculator.Calculate($"({a})/(({b})+tan(({c})))"));
+        Assert.Equal(a/(b+Math.Tan(c)), 
+            Calculator.Calculate($"({a})/(({b})+tan(({c})))"), 
+            FunctionTests.PRECISION);
 }
\ No newline at end of file
diff --git a/SharpCalculator.Tests/FunctionTests.cs b/SharpCalculator.Tests/FunctionTests.cs
index c59c083..5487b25 100644
--- a/SharpCalculator.Tests/FunctionTests.cs
+++ b/SharpCalculator.Tests/FunctionTests.cs
@@ -2,6 +2,8 @@
 
 public class FunctionTests
 {
+    public const int PRECISION = 8;
+    
     public FunctionTests()
     {
         CultureInfo.DefaultThreadCurrentCulture = CultureInfo.InvariantCulture;
@@ -12,32 +14,56 @@ public class FunctionTests
     [InlineData(1)]
     [InlineData(-3)]
     [InlineData(-2)]
+    [InlineData(Math.PI/4)]
+    [InlineData(Math.PI/2)]
+    [InlineData(Math.PI*3/4)]
+    [InlineData(Math.PI*2)]
+    [InlineData(999)]
+    [InlineData(-999)]
     public void Sin(double a) => 
-        Assert.Equal(Math.Sin(a), Calculator.Calculate($"sin({a})"));
+        Assert.Equal(Math.Sin(a), Calculator.Calculate($"sin({a})"), PRECISION);
 
     [Theory]
-    [InlineData(0.9)]
+    [InlineData(5)]
     [InlineData(1)]
     [InlineData(-3)]
     [InlineData(-2)]
+    [InlineData(Math.PI/4)]
+    [InlineData(Math.PI/2)]
+    [InlineData(Math.PI*3/4)]
+    [InlineData(Math.PI*2)]
+    [InlineData(999)]
+    [InlineData(-999)]
     public void Cos(double a) => 
-        Assert.Equal(Math.Cos(a), Calculator.Calculate($"cos({a})"));
+        Assert.Equal(Math.Cos(a), Calculator.Calculate($"cos({a})"), PRECISION);
 
     [Theory]
-    [InlineData(0.9)]
+    [InlineData(5)]
     [InlineData(1)]
     [InlineData(-3)]
     [InlineData(-2)]
+    [InlineData(Math.PI/4)]
+    [InlineData(Math.PI/1.99)]
+    [InlineData(Math.PI*3/4)]
+    [InlineData(Math.PI*1.99)]
+    [InlineData(999)]
+    [InlineData(-999)]
     public void Tan(double a) => 
-        Assert.Equal(Math.Tan(a), Calculator.Calculate($"tan({a})"));
+        Assert.Equal(Math.Tan(a), Calculator.Calculate($"tan({a})"), PRECISION);
 
     [Theory]
-    [InlineData(0.9)]
+    [InlineData(5)]
     [InlineData(1)]
     [InlineData(-3)]
     [InlineData(-2)]
+    [InlineData(Math.PI/4)]
+    [InlineData(Math.PI/2)]
+    [InlineData(Math.PI*3/4)]
+    [InlineData(Math.PI*1.99)]
+    [InlineData(999)]
+    [InlineData(-999)]
     public void Ctg(double a) => 
-        Assert.Equal(1 / Math.Tan(a), Calculator.Calculate($"ctg({a})"));
+        Assert.Equal(1 / Math.Tan(a), Calculator.Calculate($"ctg({a})"), PRECISION);
 
     [Theory]
     [InlineData(0.9)]
@@ -45,7 +71,7 @@ public class FunctionTests
     [InlineData(-3)]
     [InlineData(-2)]
     public void Asin(double a) => 
-        Assert.Equal( Math.Asin(a), Calculator.Calculate($"asin({a})"));
+        Assert.Equal( Math.Asin(a), Calculator.Calculate($"asin({a})"), PRECISION);
 
     [Theory]
     [InlineData(0.9)]
@@ -53,7 +79,7 @@ public class FunctionTests
     [InlineData(-3)]
     [InlineData(-2)]
     public void Acos(double a) => 
-        Assert.Equal( Math.Acos(a), Calculator.Calculate($"acos({a})"));
+        Assert.Equal( Math.Acos(a), Calculator.Calculate($"acos({a})"), PRECISION);
 
     [Theory]
     [InlineData(0.9)]
@@ -61,7 +87,7 @@ public class FunctionTests
     [InlineData(-3)]
     [InlineData(-2)]
     public void Atan(double a) => 
-        Assert.Equal( Math.Atan(a), Calculator.Calculate($"atan({a})"));
+        Assert.Equal( Math.Atan(a), Calculator.Calculate($"atan({a})"), PRECISION);
 
     [Theory]
     [InlineData(0.9)]
@@ -69,7 +95,7 @@ public class FunctionTests
     [InlineData(-3)]
     [InlineData(-2)]
     public void Actg(double a) => 
-        Assert.Equal( Math.Atan(1 / a), Calculator.Calculate($"actg({a})"));
+        Assert.Equal( Math.Atan(1 / a), Calculator.Calculate($"actg({a})"), PRECISION);
 
     [Theory]
     [InlineData(0.9)]
@@ -77,5 +103,5 @@ public class FunctionTests
     [InlineData(-3)]
     [InlineData(-2)]
     public void Ln(double a) => 
-        Assert.Equal( Math.Log(a), Calculator.Calculate($"ln({a})"));
+        Assert.Equal( Math.Log(a), Calculator.Calculate($"ln({a})"), PRECISION);
 }
\ No newline at end of file