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Ask Chemistry

Balancing GRE equation

This is a problem from the GRE practice exam published by ETS. They don’t have explanations for the answer key and I’m wondering what is the best way to balance the equation? Thanks!

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Cryptocurrency Ethereum Mastering Development

List ERC20 token on exchange development

I’m developing an exchange. When a new user register on website we will create new eth wallet for them. When they deposit USDT on their wallet how can I transfer that USDT amount to another address (pool) and pay gas fee with another account (because new user’s eth balance is 0)?

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Mastering Development

Ordered list of points along polylines/curves on an image

I have images with some combination of polylines/polycurves. My aim is to recover an ordered list of points for these polylines/polycurves. Using opencv connectedComponents I can isolate each of these polylines/curves in the image, and then I tried to get an ordered sequence of points with these steps: num_labels, labels_im = cv2.connectedComponents(input_image) ske = skimage.morphology.skeletonize(labels_im==1) […]

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Mastering Development

Docker container networking does not translate service name to IP address

I have two spring boot applications, one that acts as an OAuth2 server and the other one as an OAuth2 client. Authorization works when I run applications as standalone applications, but I am having an issue when I run them in separate Docker containers, using docker compose. My client app has two endpoints, / and […]

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Mastering Development

How can you just switch a boolean value?

This sounds like a really simple question but I couldn’t figure out the answer. How can you just switch a boolean value without knowing what it is. It’s obvious how to make something true into false, and something false into true, but how do you just switch between true and false and make a boolean […]

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Linux Mastering Development

what is different between red file and green file in Terminal (macOS)

I have 2 backup files but they have 2 different colors? So what is different between red file and green file in Terminal (macOS)

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Mastering Development

Connection refused React App requesting from Node app running on a different port

I have been trying to make a PERN stack app. It works locally but when I put it onto AWS, the api calls to the Node backend get a ERRCONNECTIONREFUSED on google chrome. My react app is on port 5000 and Node on 8000. I have them both running with pm2. I have built the […]

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Linux Mastering Development

Set CPU to high performance

I spent hours searching for an answer in Internet. All I could find doesn’t help. I have Intel i9-9980HK, running under Ubuntu 20.04, kernel 5.4.0-33. The problem is that under the full load the CPU lowers the frequency to 2.7 GHZ, I guess in order to stay under low power budget. Whatever I try I […]

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Mastering Development

On refresh, Angular app says “Template error: Can’t bind to ‘myprop’ since it isn’t a known property of ‘app-my-component'”

In my simple Angular app, I have this code in app.component.html <app-my-component [myProp]=”thepropvar”></app-my-component> It works when I do ng serve –aot, but when I make a change, it refreshes, and puts this error in the console: core.js:4002 ERROR Error: Template error: Can’t bind to ‘myprop’ since it isn’t a known property of ‘app-my-component’ It completely […]

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Mastering Development

Pseudo element ::before doesn’t show background image [duplicate]

I’m simply doing div with pseudo element ::before and somehow background image doesn’t show i read somewhere you must be set your parent height but still doesn’t work. body { width: auto; height: auto; font-family: ‘Roboto’, sans-serif; } .hero-shot { width: 100%; height: auto; margin: 0 auto; text-align: center; } .hero-shot::before { content: “”; width: […]