The linear approximation is the line that approximates the function near a specified point. In this case you want the line, y = mx + b, that approximates the function at x = 1.
Well, the slope of the line is easy, it's just the first derivative at x = 1:
Now we need the y-intercept for the line. We know a point on this line: It is (1, f(1)) = (1, 2).
Thus your linear approximation to y = f(x) at x = 1 is .
See if you can take it from here.