diff --git a/src/plugins.js b/src/plugins.js
index 69b2ca3..095008d 100644
--- a/src/plugins.js
+++ b/src/plugins.js
@@ -1156,7 +1156,7 @@ GA.plugins = function(ga) {
     //Sine
     sine: function(x) {return Math.sin(x * Math.PI / 2);},
     sineSquared: function(x) {return Math.pow(Math.sin(x * Math.PI / 2), 2);},
-    sineCubed: function(x) {return Math.pow(Math.sin(x * Math.PI / 2), 2);},
+    sineCubed: function(x) {return Math.pow(Math.sin(x * Math.PI / 2), 3);},
     inverseSine: function(x) {return 1 - Math.sin((1 - x) * Math.PI / 2);},
     inverseSineSquared: function(x) {return 1 - Math.pow(Math.sin((1 - x) * Math.PI / 2), 2);},
     inverseSineCubed: function(x) {return 1 - Math.pow(Math.sin((1 - x) * Math.PI / 2), 3);},
@@ -4556,7 +4556,7 @@ GA.plugins = function(ga) {
   //`requestFullscreen` is used by `enableFullscreen` to launch
   //fullscreen mode.
   ga.requestFullScreen = function() {
-    if (!document.fullscreenEnabled) {
+    if (document.fullscreenEnabled && document.fullscreenElement !== null) {
       ga.canvas.requestFullscreen();
     }
   };
@@ -4564,7 +4564,7 @@ GA.plugins = function(ga) {
   //`exitFullscreen` is used by `enableFullscreen` to exit
   //fullscreen mode.
   ga.exitFullScreen = function() {
-    if (document.fullscreenEnabled) {
+    if (document.fullscreenEnabled && document.fullscreenElement === null) {
       document.exitFullscreen();
     }
   };