Answer:
Part 5.1.1:

Part 5.1.2:

Step-by-step explanation:
We are given that:

Part 5.1.1
Recall that:

Let θ = 2<em>A</em>. Hence:

Square the original equation:

Hence:

Subtract:

Take the square root of both sides:

Since 0° ≤ 2<em>A</em> ≤ 90°, cos(2<em>A</em>) must be positive. Hence:

Part 5.1.2
Recall that:

We can use the third form. Substitute:

Solve for cosine:

In conclusion:

(Note that since 0° ≤ 2<em>A</em> ≤ 90°, 0° ≤ <em>A</em> ≤ 45°. Hence, cos(<em>A</em>) must be positive.)
Answer:
False
Step-by-step explanation:
It's actually C=πd d is diameter or C=πr^2
Answer:
the best way is to follow the law, sales tax is not subject to discount by the seller.
Step-by-step explanation:
both ways result in the same outcome:
improper way, discount after tax
$50+$5(tax)=$55, after discount $55-$11(20%)=$44
proper way, discount before tax
$50-$10(20%)=$40+$4(tax)=$44