Find an equation of the tangent line at the point specified.
y = 3·sin(x) + 4·cos(x), x = 0
Recall that a tangent line to a graph of y = f(x) at a point P(a, f(a)) is the line through the point P of slope . The equation of the tangent line in point-slope form is
y - = (x-a).
We find the formula for the slope of the tangent line to the graph of y = f(x) for any value of x by calculating f'(x).
f(x) = 3·sin(x) + 4·cos(x)
= · + ·
The slope of the tangent line to the graph is given by f'(x) = 3·cos(x) − 4·sin(x). The slope of this line at x = 0 is found by evaluating f'(0).
f'(x) = 3·cos(x) - 4·sin(x)
f'(0) =
Find the equation of the tangent line to f(x) of slope 3 at the point (0, 4).
y - f(0) = f'(0)(x-0)
y - = · (x-0)