Update index.html

Author: Gmac4247

index.html

@@ -992,27 +992,19 @@ <h4 style="font-size:160%;margin:7px">Trigonometry</h4>
   return bestMatch;
 }
 
-	
- function Atan(input) {
-  // Normalize and extract the value: "atan 0.5" or "atan(0.5)"
-  const match = input.match(/atan\s*\(?([0-9./\s√-]+)\)?/i);
-  if (!match) return; // Invalid format
-
-  const inputStr = match[1].trim();
-  const x = parseFloat(eval(inputStr.replace(/√(\d+)/g, 'Math.sqrt($1)')));
-
-  if (isNaN(x) || x <= 0 ) return; // Domain cutoffs from your spec
+function Atan(x) {
+if (typeof x !== 'number' || isNaN(x) || x <= 0) return null;
 
-  // Case A: x > 1 or x < 0.089 → direct match
-  if (x > 1 || x < 0.089) {
-    const bestMatch = closestValue(x, 'tan');
-    if (bestMatch) return `atan(${inputStr}) ≈ ${bestMatch.angle}`;
-  }
+// Direct match zone
+if (x > 1 || x < 0.089) {
+  const match = closestValue(x, 'tan');
+  return match?.angle ?? null;
+}
 
-  // Case B: 0.089 < x < 1 → invert to 1/x and search tan table
-  const reciprocal = 1 / x;
-  const bestMatch = closestValue(reciprocal, 'tan');
-  if (bestMatch) return `atan(${inputStr}) ≈ ${bestMatch.angle}`;
+// Reflective zone (0.089 < x < 1)
+const reciprocal = 1 / x;
+const match = closestValue(reciprocal, 'tan');
+return match?.angle ?? null;
 }
 
 </script>
@@ -1343,7 +1335,7 @@ <h6 style="font-size:160%;margin:7px">Area of a circle</h6>
   }
 
   const thing = 2 * height / length;
-  const angle = parseFloat(atan(thing).toFixed(5));
+  const angle = parseFloat(Atan(thing).toFixed(5));
   const cosine = parseFloat(cos(angle).toFixed(5));
   const radius = length / (2 * cosine);
 
@@ -2443,11 +2435,13 @@ <h6 style="font-size:160%;margin:7px">Area of a circle</h6>
       const s = sin(angle);
       const c = cos(angle);
       const t = tan(angle);
+	    const at = Atan(angle);
 
       output.innerText += `✅ Testing angle: ${angle}\n\n`;
       output.innerText += `• sin(${angle}) = ${s}\n`;
       output.innerText += `• cos(${angle}) = ${c}\n`;
       output.innerText += `• tan(${angle}) = ${t}\n`;
+      output.innerText += `• Atan(${angle}) = ${at}\n`;
 
 
       // Optional: known expectations