Answer:

Step-by-step explanation:
We want to write the trignometric expression:

As an algebraic equation.
First, we can focus on the inner expression. Let θ equal the expression:

Take the secant of both sides:

Since secant is the ratio of the hypotenuse side to the adjacent side, this means that the opposite side is:

By substitutition:

Using an double-angle identity:

We know that the opposite side is √(u² -100), the adjacent side is 10, and the hypotenuse is u. Therefore:

Simplify. Therefore:

Answer:
13 centimeters per day.
Step-by-step explanation:
We have been given that during summer, the water level of the river increased by 78 centimeters in 6 days. We are asked to find the water level increase rate in centimeters per day.
To find the water level increase rate per day, we will divide total increase by total days as:


Therefore, the water level increase rate is 13 centimeters per day.
Answer:
=> Apply law of cosine

=> input value

=> simplify

=> calulcation

=> apply rule: Distance must be greater than 0
which is about 14.51828
Answer:
B
Step-by-step explanation:
Pythagorean theorem (applicable on right triangles only) says:

- Where
and
are the two legs of the triangle and
is the length of the hypotenuse [THE LONGEST SIDE].
<u>We can square each leg on the triangle and take the sum, if that is equal to the square of the longest side, we have a right triangle. Let's check for all of these.</u>
A.


They're not right triangle.
B.


This is a right triangle.
C.


They're not right triangle.
D.


They're not right triangle.
Only B is the right triangle.