Question

Use the definition mtan = lim h-0 f(a+h)-f(a) h b. Determine an equation of the tangent line at P. f(x)=√√3x +7, P(3,4) + a. mtan (Simplify your answer. Type an exact answer, using radicals as needed.) to find the slope of the line tangent to the graph off at P ...

Answer 1

First, we need to find mtan using the given formula:

mtan = lim h→0 [f(a+h) - f(a)] / h

Plugging in a = 3 and f(x) = √(√3x + 7), we get:

mtan = lim h→0 [√(√3(3+h) + 7) - √(√3(3) + 7)] / h

Simplifying under the square roots:

mtan = lim h→0 [√(3√3 + √3h + 7) - 4] / h

Multiplying by the conjugate of the numerator:

mtan = lim h→0 [(√(3√3 + √3h + 7) - 4) * (√(3√3 + √3h + 7) + 4)] / (h * (√(3√3 + √3h + 7) + 4))

Using the difference of squares:

mtan = lim h→0 [(3√3 + √3h + 7) - 16] / (h * (√(3√3 + √3h + 7) + 4))

Simplifying the numerator:

mtan = lim h→0 [(√3h - 9) / (h * (√(3√3 + √3h + 7) + 4))]

Using L'Hopital's rule:

mtan = lim h→0 [(√3) / (√(3√3 + √3h + 7) + 4)]

Plugging in h = 0:

mtan = (√3) / (√(3√3 + 7) + 4)

Now we can use this to find the equation of the tangent line at P(3,4):

m = mtan = (√3) / (√(3√3 + 7) + 4)

Using the point-slope form of a line:

y - 4 = m(x - 3)

Simplifying and putting in slope-intercept form:

y = (√3)x/ (√(3√3 + 7) + 4) - (√3)9/ (√(3√3 + 7) + 4) + 4

This is the equation of the tangent line at P.