fix some typos in the documentation.

modules/core/include/opencv2/core/persistence.hpp

@@ -108,7 +108,7 @@ XML/YAML/JSON file storages.     {#xml_storage}
 Writing to a file storage.
 --------------------------
 You can store and then restore various OpenCV data structures to/from XML (<http://www.w3c.org/XML>),
-YAML (<http://www.yaml.org>) or JSON (<http://www.json.org/>) formats. Also, it is possible store
+YAML (<http://www.yaml.org>) or JSON (<http://www.json.org/>) formats. Also, it is possible to store
 and load arbitrarily complex data structures, which include OpenCV data structures, as well as
 primitive data types (integer and floating-point numbers and text strings) as their elements.
 
@@ -155,7 +155,7 @@ Here is an example:
         return 0;
     }
 @endcode
-The sample above stores to XML and integer, text string (calibration date), 2 matrices, and a custom
+The sample above stores to YML an integer, a text string (calibration date), 2 matrices, and a custom
 structure "feature", which includes feature coordinates and LBP (local binary pattern) value. Here
 is output of the sample:
 @code{.yaml}

modules/imgproc/src/deriv.cpp

@@ -444,7 +444,7 @@ void cv::Sobel( InputArray _src, OutputArray _dst, int ddepth, int dx, int dy,
     if( scale != 1 )
     {
         // usually the smoothing part is the slowest to compute,
-        // so try to scale it instead of the faster differenciating part
+        // so try to scale it instead of the faster differentiating part
         if( dx == 0 )
             kx *= scale;
         else