District 1 2011

[bs42]

I feel like these are such easy points to get:

f(x) = (2x-3)/5x. Find f'(7)
I sort of figured that this was a derivative problem, but don't know how to go about it besides typing it in into my calculator.

If y = 2x^4, then dy/dx = dx/dy

[nsguy1350]

The derivative of [unparseable or potentially dangerous latex formula] is [unparseable or potentially dangerous latex formula]. You can say here that [unparseable or potentially dangerous latex formula].

[unparseable or potentially dangerous latex formula] behaves as a quotient, so [unparseable or potentially dangerous latex formula]. The derivative and it's reciprocal here are simple: [unparseable or potentially dangerous latex formula].

[bs42]

Same test.
15. Find the radius of the circle.
Uh picture: Circle circumscribed in a triangle. triangle lengths 4 in, 5 in, 7 in

19. Find the area of the shaded region in square units.

43. (1/3) + (1/6) + (1/10) +...+ (1/91) = ?

52. Find the instantaneous rate of change of x^3 + 2x^2 - 5x -6 at x = -1

58. Let f(x) = 2x+5 and g(x) = 3x-2. If h(x) is the inverse function of f(x)/g(x), find the value of h(-4)

Thanks a lot by the way, my UIL coach really has no motive to help me with any problems.

[nsguy1350]

15. If the triangle has a circumscribed circle, then the radius is [unparseable or potentially dangerous latex formula], where a,b,c are the sides, and K is the area (use Heron's formula).

19. I # at those.

43. Since it's triangular numbers and they start with 1/3, just do [unparseable or potentially dangerous latex formula].

52. Evaluate the derivative at [unparseable or potentially dangerous latex formula].
[unparseable or potentially dangerous latex formula]. Evaluating gives -6.

58. [unparseable or potentially dangerous latex formula]. Set that equal to the x value of the inverse function, to get x = -3/14.

[88bobcat]

[nsguy1350]

Oh, I automatically assumed that 19 was not an integral, but a problem where they give you a shape, such as a trapezoid. I guess 88bobcat got that one for you then.