All ACT Math Resources
Example Questions
Example Question #3041 : Act Math
Right triangle has sides , and . What is the cosine of ?
SOHCAHTOA tells us that , and we know the hypotenuse is the longest side of the triangle, . Our adjacent side will be the other side that has as a vertex, .
Thus, .
Example Question #3041 : Act Math
Right triangle has sides , and . What is the cosine of ?
SOHCAHTOA tells us that , and we know the hypotenuse is the longest side of the triangle, . Our adjacent side will be the other side that has as a vertex, .
Thus, .
Example Question #1 : How To Find Positive Cosine
The value of a cosine is positive in which quadrants?
The 1st and 4th
The 3rd only
The 1st and 3rd
The 4th only
The 1st and 4th
The cosine is positive in the 1st and 4th quadrants and negative in 2nd and 3rd
Example Question #32 : Cosine
Which of the following is equal to ?
Here, we use the SOHCAHTOA ratios and the fact that csc x = 1 / sin x.
Cosine x = adjacent side length / hypotenuse length
Cosecant x = 1 / sin x = hypotenuse / opposite
(Adjacent / hypotenuse) * (hypotenuse / opposite) = Adjacent / opposite = Cotangent x.
Example Question #2 : How To Find Positive Cosine
and is between and . What is the value of ?
For to , we know that . So, the question asks, what is the value of , where . Therefore, it is asking what the value of is, which is .
Example Question #2 : How To Find Positive Cosine
To the nearest , what is the cosine formed from the origin to ? Assume counterclockwise rotation.
If the point to be reached is , then we may envision a right triangle with sides and , and hypotenuse . The Pythagorean Theorem tells us that , so we plug in and find that:
Thus,
Now, SOHCAHTOA tells us that , so we know that:
Thus, our cosine is approximately .
Example Question #131 : Trigonometry
Two drivers race to a finish line. Driver A drives north blocks, and east blocks and crosses the goal. Driver B drives the shortest direct route between the two points. Relative to east, what is the cosine of the angle at which Driver B raced? Round to the nearest .
If the point to be reached is blocks north and blocks east, then we may envision a right triangle with sides and , and hypotenuse . The Pythagorean Theorem tells us that , so we plug in and find that:
Thus,
Now, SOHCAHTOA tells us that , so we know that:
Thus, our cosine is approximately .
Example Question #1 : How To Find The Period Of The Cosine
A function with period P will repeat on intervals of length P, and these intervals are referred to as periods.
Find the period of the function
.
For the function
the period is equal to
or in this case
which reduces to .
Example Question #131 : Trigonometry
A function with period P will repeat on intervals of length P, and these intervals are referred to as periods.
Find the period of the function
.
For the function
the period is equal to
or in this case
which reduces to .
Example Question #3051 : Act Math
A function with period P will repeat on intervals of length P, and these intervals are referred to as periods.
Find the period of the function
.
For the function
the period is equal to
or in this case
which reduces to .