In Go, arrays can be either dynamically sized or fixed-size. The main difference between the two is that fixed-size arrays have a predetermined size that cannot be changed during the execution of a program, while dynamically sized arrays can grow or shrink as needed.
Fixed-size arrays are declared with a specific size, such as int for an array of 5 integers. Once declared, the size of the array cannot be changed, which means that it is not possible to add or remove elements from the array. This makes fixed-size arrays more memory efficient and faster to access, as their size is known at compile time and their memory can be allocated on the stack.
Dynamically sized arrays, on the other hand, are declared with the  syntax, such as int. The size of the array is not specified in the declaration, and elements can be added or removed from the array dynamically using the append() function. This makes dynamically sized arrays more flexible, as their size can be adjusted as needed during the execution of a program. However, this also makes them less memory efficient and slower to access, as their size is not known at compile time and their memory must be allocated on the heap.
Overall, fixed-size arrays are useful for situations where the size of the array is known in advance and will not change, such as for small arrays used for static data. Dynamically sized arrays are useful for situations where the size of the array may change during the execution of a program, such as for dynamic data structures like lists or queues.