User talk:157.33.195.130

April 2019
Hello, I'm Serols. I wanted to let you know that I reverted one of your recent contributions —specifically this edit to Differentiation of trigonometric functions— because it did not appear constructive. If you would like to experiment, please use the sandbox. If you have any questions, you can ask for assistance at the Help Desk. Thanks. Serols (talk) 11:16, 13 April 2019 (UTC)
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