Update index.html

Author: Gmac4247

index.html

@@ -947,6 +947,28 @@ <h4 style="font-size:160%;margin:7px">Trigonometry</h4>
   const fallbackKey = closestRad(radian);
 return trig[fallbackKey]?.cos ?? null;
 }
+
+function tan(radian) {
+  const radKey = `rad(${radian.toFixed(3)})`;
+
+  // 🔹 Case 1: Exact match
+  if (trig[radKey]?.tan !== undefined) return trig[radKey].tan;
+
+  // 🔹 Case 2: 0.8 > x > 0.1 → Use sine reflection
+  if (radian > 0.1 && radian < 0.8) {
+    const reflected = 1.6 - radian;
+    const reflectedKey = `rad(${reflected.toFixed(3)})`;
+
+    if (trig[reflectedKey]?.tan !== undefined) return trig[reflectedKey].tan;
+
+    const fallbackKey = closestRad(reflected);
+return 1 / trig[fallbackKey]?.tan ?? null;
+  }
+
+  // 🔹 Case 3: Otherwise, search sin column directly
+  const fallbackKey = closestRad(radian);
+return trig[fallbackKey]?.tan ?? null;
+}
 
 
 function closestValue(input, funcType) {
@@ -2420,11 +2442,12 @@ <h6 style="font-size:160%;margin:7px">Area of a circle</h6>
     try {
       const s = sin(angle);
       const c = cos(angle);
-      
+      const t = tan(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`;
 
 
       // Optional: known expectations