Help me!
Find the values of c that satisfy the equation f(b)-f(a)/b-a= f prime(c) in the conclusion of the mean value theorem for the given function and interval. f(x)=9x+9/x [1/9, 9]
I told you how to find the answer. It is easy.
Take derivative of f(x) and solve for it equal to 0..
9-(9/x^2)
Rolle's Theorem sets the derivative = 0. The Mean Value Theorem locates the slope of a tangent line that is parallel to a secant of given endpoints. In this case,you want to find the slope of the tangent line of the given function at point c that is parallel to the secant line of the given endpoints. Then find the value of c for the given function that gives you the equation of that line.
can you show me please?
f(b)-f(a)/b-a is formula for finding the slope of the secant. Your endpoints are 1/9 and 9 (a = 1/9 and b = 9) Substitute those in to the above formula, and that will be the slope of the secant AND the slope of the tangent line at point [c, f(c)] Find f'(x) [you've already found f'(x), I see]. Now substitute c for x: f'(c) = 9c - 9/c^2. That is the slope of the tangent line at point c. Set that equal to the slope of the secant line. 9c - 9/c^2 = slope of tangent line (which you solved for earlier). Now solve for c!
I'm having difficulty finding the slope of the secant and tangent line
The slope of the secant is the same as the slope of any line: m = y2 - y1/(x2 - x1) In this case, the slope is given by f(b) - f(a)/(x - a) Since f(x) = 9x + 9/x, f(b) = 9(9) + 9/9 and f(a) = 9(1/9) + 9/(1/9) b - a = 9 = 1/9 Do the math! That is the slope of the secant.
b - a = 9 - 1/9
f(b)=82 f(a)=82
f(b)-f(a)=0
what am I doing wrong??
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