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Rehana Hassan Muhumed
Rehana Hassan Muhumed

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Day 2 — Understanding Cost Function & Gradient Descent

Today I continued my Machine Learning journey and explored two very important concepts: the cost function and gradient descent.

At first, these topics felt a bit confusing, but breaking them down into simple ideas helped me understand them better.

📌 Cost Function

The cost function is used to measure how accurate or inaccurate a model’s predictions are.

  • A high cost means the model is making large errors
  • A low cost means the model is performing well

The main goal in machine learning is to reduce this cost as much as possible to improve the model’s performance.


📉 Gradient Descent

Gradient descent is an algorithm used to minimize the cost function.

It works by:

  • Starting with initial values for the model parameters
  • Adjusting them step by step
  • Moving in the direction that reduces the error

I like to think of it as trying to reach the bottom of a valley, where the lowest point represents the best possible model.


⚡ Learning Rate

Another key concept I learned is the learning rate, which controls how big each step is during gradient descent.

  • A small learning rate makes learning slow but stable
  • A large learning rate makes learning faster but can be unstable

Choosing the right learning rate is important for finding the optimal solution efficiently.


🧠 Reflection

This topic was challenging, especially understanding how the model updates its parameters. However, visualizing the process as moving down a curve helped me understand the overall idea.

I’m still getting comfortable with these concepts, but I’m starting to see how models improve step by step.


🚀 Learning Machine Learning one step at a time.

MachineLearning #AI #LearningJourney

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