Recent content by chaosblack

dy/dx = 5u(5u^2 - 3)^-1/2 x (2(3x+1)^-1 - 6x(3x+1)^-2) From here do I just sub in for u?

u = (2x)(3x+1)^-1 u' = 2(3x+1)^-1 + (2x)(-1)(3x+1)^2(3) = 2(3x+1)^-1 - 6x(3x+1)^-2 This?

u = \frac{2x}{3x+1} u = (2x)(3x+1)^-1 u' = -2x(3x+1)^-2 x (3) u' = -6x(3x+1)^-2 Did I do something wrong?

Homework Statement Find \frac{dy}{dx} if y = \sqrt{5u^2 -3} and u = \frac{2x}{3x+1} Homework Equations Chain Rule \frac{dy}{dx} = \frac{dy}{du} x \frac{du}{dx} The Attempt at a Solution \frac{dy}{du} = 5u(5u^2 - 3)^-1/2 \frac{du}{dx} = -6x(3x+1)^-2 \frac{dy}{dx} =...

Yeah sorry, I edited the original questions (and know I know how to show the limit's now haha). So then my answers for 10/x would be 0. the one with "a" as a variable would be 0. and then the one with the absolute would be 1?

Before we start, can you just explain how to start me off? I understand the idea of all limits, just a few tricky ones that were assigned for homework. (note: ALL limits are x --> infinity) Homework Statement lim ^{}\frac{10}{x}lim \frac{x^{2}+a^{2}}{x^{3}+a^{3}}lim (1 - r^{x}) , |r| < 1...

okay thanks a lot

okay thanks, so the answer would just be the derivative set equal to 0?

For which value of x...horizontal Tangent Line Homework Statement For which value of x does f(x) = \frac{k}{ax^{2}+bx+c} have a horizontal tangent line? Homework Equations Quotient Rule? F'(x) = [g(x)a'(x) - a(x)g'(x)]/g(x)^2? The Attempt at a Solution Am I supposed to...

Homework Statement Supposed "f" is a differentiable function. Write the expression for the derivative of the following function. a) h(x) = -4x^3 * f(x) b) h(x) = 2/\sqrt{x}* f(x) Homework Equations N/a The Attempt at a Solution Would the answers just be (using the product...

haha...thanks man. I'm starting to forget to most simple stuff

Okay thanks a lot, I updated the thread with a different question lol

simple SIMPLE local extremia question Homework Statement Find the absolute maximum and absolute minimum values of f(x) = 3x^4 - 8x ^3 + 12x^2 -48x +25, where 0 <= x <= 3. Homework Equations N/a The Attempt at a Solution f'(x) = 12x^3 - 24x^2 + 24x -48 = 12 (x^3 - 2x^2 +...

what did you get for your "r" value? I'm doing somethign wrong...

ah sorry, its actually supposed to be "/2", that way its half the area, sorry the drawing didnt show up. its supposed to be a semi-circle connected to a rectangle. sorry, that was a typing error as well haha. A = L * D + (pi*d)/2 which becomes A = 8 - d/2 - ((pi * d)/4) this still...