Final answer:
To calculate the tangent line at a specific point on a curve, you need the slope of the curve at that point and the y-value at that x-point. With that information, the equation of the tangent line can be written in point-slope form.
Step-by-step explanation:
When calculating the tangent line to a curve at a given x-point, what is usually required is the slope of the curve at that point, which is also known as the derivative of the curve at that point. The equation of the curve is also necessary in order to find the slope, as well as to determine the specific y-value at the x-point in question. Once you have the slope and the y-value, you can use the point-slope form (y - y1) = m(x - x1) to write the equation of the tangent line, where m is the slope and (x1, y1) are the coordinates of the given point on the curve.