Recent content by Econguy

An Isosceles triangle has two equal sides of length 10cm. Let x be the angle between the two equal sides. a. Express the area A of the triangle as a function of x in radians. b. Suppose that x is increasing at the rate of 10 degrees per minute. How fast is A changing at the instant x =...

Thanks for the response: Am I on the right track... 2x(x^2 + 9)[(x^2 + 9)(-1)] - [(2x)(x^2 + 9) (18 - 2x^2)] at this point I'm not clear how the 2x from the second term disappears (i.e is factored out..). I understand in what I just did nothing has been factored yet, just rewritten...

I am taking an online Introductory Calculus course. I have a decent understanding thus far, however, the problem I'm working on gets somewhat messy and I am having a difficult time simplyifing the answer. f"(x) = (x^2 + 9)^2 (-2x) - [(9 - x^2)(2)(x^2 + 9)(2x)]/(x^2 + 9)^4 the solutions manual...