Here is a practice question on parabolas in the coordinate plane.

What does $i – i^2 + i^3 – i^4 + \cdots + i^{97} – i^{98}$ equal, where the imaginary number $i$ is defined as $i^2=-1$ ?

- $\quad -i-1$
- $\quad -i+1$
- $\quad 0$
- $\quad i-1$
- $\quad i+1$

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Here is a practice question on parabolas in the coordinate plane.

What does $i – i^2 + i^3 – i^4 + \cdots + i^{97} – i^{98}$ equal, where the imaginary number $i$ is defined as $i^2=-1$ ?

- $\quad -i-1$
- $\quad -i+1$
- $\quad 0$
- $\quad i-1$
- $\quad i+1$

I just published the playlist of video explanations to all of the math questions in the Decemeber 2014 ACT 72G test.

Here is a practice question on simplifying trigonometric expressions.

For all $\theta$, $\quad \sin \theta + {(\cot \theta})(\cos{\theta})$ is equivalent to

- $\quad \csc \theta$
- $\quad \sec \theta$
- $\quad \cot \theta$
- $\quad \tan \theta$
- $\quad \cos \theta$

Here is a practice question on straight lines in the coordinate plane.

If the point $(a, -2)$ falls on the straight line $2y-3x=-6$ in the standard $(x, y)$ coordinate plane, then $a=$ ?

- $\quad -\dfrac{3}{2}$
- $\quad -\dfrac{2}{3}$
- $\quad \dfrac{2}{3}$
- $\quad \dfrac{3}{2}$
- $\quad \dfrac{10}{3}$

Here is a practice question on how the volume of a cylinder varies with its height and radius.

The radius of a right circular cylinder is doubled and the height of the cylinder is halved to form a new right circular cylinder. The volume of the new

cylinder is how many times the volume of the original cylinder?

- $\quad \dfrac{1}{4}$
- $\quad \dfrac{1}{2}$
- $\quad 1$
- $\quad 2$
- $\quad 4$