here's a quick video on derivatives in calculus so let's say i want to find the derivative of this function at x equals 3. so to solve this problem i need to find the derivative f prime of x which is just the derivative of this function with respect to x so what i can do is use the power rule shortcut where i take the power of each variable i multiply it by the front of that variable and then i subtract 1 from the power so doing this power rule i'm going to end up with 3x squared for this first term and i'm going to end up with just five for this second term i need to evaluate this at x equals three so f prime of three is going to be equal to three times three squared minus five three squared times three is 27 and then i subtract off this 5 i'm going to end up with 22. this value basically tells us that if we look at our function at x equals 3 the rate of change at this specific point is equal to 22. that's the idea of derivatives in less than a minute