$\Delta$ denotes the symmetric difference operator defined as $A\Delta B=(A\cup B)-(A\cap B)$, where A and B are sets. Is $\Delta$ commutative? If so, prove it; otherwise, give a counterexample.

Determine the critical numbers of the given function and classify each critical point as a relative maximum, a relative minimum, or neither. $f(t)=2 t^{3}+6 t^{2}+6 t+5$

Add: 70.02 + 0.0013 + 9.062 + 0.142

When the first two astronauts landed on the Moon, a third astronaut remained in an orbiter in circular orbit near the Moon’s surface. During half of every complete orbit, the orbiter was behind the Moon and out of radio contact with the Earth. On each orbit, how long was the time when radio contact was lost?

Find each sale price. $520 TV; 18% off.

What is the term for the release of harmful substances into the environment? a.pollutant b.sediment c.sewage d.pollution

The following excerpts appear in a guide for preparing income tax reports. Source: Your Income Tax 2014. (a) The tax law provides several tax benefits for people attending school. (b) If you use the Tax Table, you do not have to compute your tax mathematically. (c) You may not deduct the expenses of seeking your first job. (d) Make sure the names used when you and your spouse file your joint return match the names you have provided to the Social Security Administration.

Write the negation of statement (c).

Evaluate the following integrals.

$$\int \frac{\cos 7 w}{16+\sin ^{2} 7 w} d w$$

Write a formula for the area of a circle of radius r.

Use the change-of-base rule (with either common or natural logarithms) to find each logarithm to four decimal places. $\log _{7} 4$

Write $\subseteq$ or $\nsubseteq$ in each blank so that the resulting statement is true. {2, 4, 6}____$\varnothing$

Six friends split the cost of a party. Each person also spends $65 for a hotel room. Each person spends$160 on the party and a room. What is the cost of the party?

The binomial a^2-b^2 is called a difference of _ and factors as _.

Evaluate the expression. Give exact answers. $\frac{3}{4} \sqrt[4]{10,000}$