Bin's blog on IT, math, physics and other science topics

Trigonometric Formulae on From Sum and Difference Formulae  of Sine and Cosine To  get Sum and Difference Formulae    of Tangent    From Sum and Difference Formulae  To  get Product to Sum Formulae From Sum and Difference Formulae  To get Sum to Product Formulae  Pythagorean Identities and  Exercises From Sum Formulae to  get Double Angle Formulae From Double Angle Formulae Cosine   To get Half Angle Formulae  Exercises 

AWS - Amazon Web Service Setup cloudwatch custom metrics for windows Use AWS CloudTrail to detect an event and send email via AWS CloudAlarm Calculus Relate 5 definitions of the number e IB Math HL Exploring Trigonometric Formulas Vector Concepts and Operations

Use AWS CloudTrail to detect an event and send email via AWS CloudAlarm Following 4 steps to accomplish this: 1.        Create a cloud trail to track the event you want to catch. 2.        Configure a CloudWatch log for the cloud trail. 3.        Create a metric filter for the CloudWatch log. 4.        Create a cloud alarm with the metric filter which will send you email when the event happens. Where the first 2 steps are working on the CloudTrail console and the last 2 steps are working on the CloudWatch console. Open the CloudTrail console at https://console.aws.amazon.com/cloudtrail/ Click the ‘Create trail’ button to create the trail to track the event you want to catch if you don’t have one. If you already have the cloud trail to trach the event you want to catch, click the trail name will bring the ‘Configuration’ page of the trail: ...

Vector definition,addition subtraction and scalar multiplication Key examples for solid understanding of  Vector definition,addition subtraction and scalar multiplication   The scalar product(dot product, inner product) of 2 vectors   Vector projection and example Cross product of 2 vectors Lines and planes 4 key aspects about lines and planes: 1.Equations: vector form, parametric form and Cartesian form, conversion between different forms, find the equations(ie,give 2 points to find the equation of a line, give 3 points to find the equation of a plane, give 2 lines to find the equation of a plane, give a equation of a plane to find another plane which is parallel to the given plane). 2.Intersections: line and line, line and plane, plane and plane. Line and line could have no intersection because they are parallel or skew. To find the intersection between a line and plane, just plug the parametric format of the line to the...

Setup   cloudwatch custom metrics for windows       --send windows performance counters to cloudwatch To monitor memory or disk usage of an EC2 windows instance with cloudwatch, we can setup cloudwatch custom metrics and send windows performance counters to cloudwatch. For Ec2Config service version prior to 4.2, we can accomplish this with EC2Config service by enabling CloudWatch integration.    https://blog.cloudthat.com/aws-cloudwatch-custom-metrics-windows/ However,   EC2Config service is no longer supports enabling CloudWatch integration after version 4.2.   Now that in the EC2ConfigService Settings window, the Cloud Watch Integration Checkbox disappears.   Even the CloudWatch Logs section is not there anymore.   Searching from the internet, many would tell you to get the latest version of EC2Config. That is because the Cloud Watch Integration only available for EC2Config version should be 2.2...