The first thing you have to realize is that tangent is the slope of a curve on a given point. You can solve for the slope by finding the derivative of the given function. So:
Next use product rule (I recommend watching videos if you're confused):
Next substitute you x-value (π/2) into your derivative:
So our slope at π/2 is 1. Next we use our slope-form and substitute our given value and solve for y-intercept (algebra-stuff)
Writing down your grades after each test gives you an accurate and recent set of data to consistently look at and monitor. Whether you progress or degrees, you are still monitoring the data.