diff --git a/demos/chartinteractions/chart.cpp b/demos/chartinteractions/chart.cpp
index a193abb..5a52a23 100644
--- a/demos/chartinteractions/chart.cpp
+++ b/demos/chartinteractions/chart.cpp
@@ -21,7 +21,7 @@
 #include "chart.h"
 #include <QValueAxis>
 #include <QAbstractAxis>
-#include <cmath>
+#include <qmath.h>
 
 Chart::Chart(QGraphicsItem *parent, Qt::WindowFlags wFlags, QLineSeries *series)
     : QChart(QChart::ChartTypeCartesian, parent, wFlags), m_series(series)
@@ -48,7 +48,7 @@ void Chart::clickPoint(const QPointF &point)
 
 qreal Chart::distance(const QPointF &p1, const QPointF &p2)
 {
-    return sqrt((p1.x() - p2.x()) * (p1.x() - p2.x())
+    return qSqrt((p1.x() - p2.x()) * (p1.x() - p2.x())
                 + (p1.y() - p2.y()) * (p1.y() - p2.y()));
 }
 
diff --git a/demos/qmloscilloscope/datasource.cpp b/demos/qmloscilloscope/datasource.cpp
index 457d796..063fb39 100644
--- a/demos/qmloscilloscope/datasource.cpp
+++ b/demos/qmloscilloscope/datasource.cpp
@@ -23,7 +23,7 @@
 #include <QAreaSeries>
 #include <QDeclarativeView>
 #include <QDebug>
-#include <cmath>
+#include <qmath.h>
 
 QTCOMMERCIALCHART_USE_NAMESPACE
 
@@ -69,7 +69,7 @@ void DataSource::generateData(int type, int rowCount, int colCount)
             switch (type) {
             case 0:
                 // data with sin + random component
-                y = sin(3.14159265358979 / 50 * j) + 0.5 + (qreal) rand() / (qreal) RAND_MAX;
+                y = qSin(3.14159265358979 / 50 * j) + 0.5 + (qreal) rand() / (qreal) RAND_MAX;
                 x = j;
                 break;
             case 1:
diff --git a/demos/quick2oscilloscope/datasource.cpp b/demos/quick2oscilloscope/datasource.cpp
index b74562c..e48f5ec 100644
--- a/demos/quick2oscilloscope/datasource.cpp
+++ b/demos/quick2oscilloscope/datasource.cpp
@@ -24,7 +24,7 @@
 #include <QtQuick/QQuickView>
 #include <QtQuick/QQuickItem>
 #include <QDebug>
-#include <cmath>
+#include <qmath.h>
 
 QTCOMMERCIALCHART_USE_NAMESPACE
 
@@ -70,7 +70,7 @@ void DataSource::generateData(int type, int rowCount, int colCount)
             switch (type) {
             case 0:
                 // data with sin + random component
-                y = sin(3.14159265358979 / 50 * j) + 0.5 + (qreal) rand() / (qreal) RAND_MAX;
+                y = qSin(3.14159265358979 / 50 * j) + 0.5 + (qreal) rand() / (qreal) RAND_MAX;
                 x = j;
                 break;
             case 1:
diff --git a/examples/scatterinteractions/chartview.cpp b/examples/scatterinteractions/chartview.cpp
index 0d53175..777930f 100644
--- a/examples/scatterinteractions/chartview.cpp
+++ b/examples/scatterinteractions/chartview.cpp
@@ -19,7 +19,7 @@
 ****************************************************************************/
 
 #include "chartview.h"
-#include <math.h>
+#include <qmath.h>
 #include <QDebug>
 
 QTCOMMERCIALCHART_USE_NAMESPACE
@@ -63,8 +63,10 @@ void ChartView::handleClickedPoint(const QPointF &point)
     QPointF closest(INT_MAX, INT_MAX);
     qreal distance(INT_MAX);
     foreach (QPointF currentPoint, m_scatter->points()) {
-        qreal currentDistance = sqrt((currentPoint.x() - clickedPoint.x()) * (currentPoint.x() - clickedPoint.x())
-                                     + (currentPoint.y() - clickedPoint.y()) * (currentPoint.y() - clickedPoint.y()));
+        qreal currentDistance = qSqrt((currentPoint.x() - clickedPoint.x())
+                                      * (currentPoint.x() - clickedPoint.x())
+                                      + (currentPoint.y() - clickedPoint.y())
+                                      * (currentPoint.y() - clickedPoint.y()));
         if (currentDistance < distance) {
             distance = currentDistance;
             closest = currentPoint;