All ACT Math Resources
Example Questions
Example Question #1 :How To Find Positive Sine
If, what is? Round to the nearest hundredth.
回想一下,正弦波symmetrical with respect to the origin. Therefore, for any value, the value foris. Therefore, ifis, then for, it will be.
Example Question #71 :Trigonometry
In a right triangle, cos(A) =. What is sin(A)?
In a right triangle, for sides a and b, with c being the hypotenuse,. Thus if cos(A) is, then c = 14, and the side adjacent to A is 11. Therefore, the side opposite of angle A is the square root of, which isSince sin is, sin(A) is.
Example Question #72 :Trigonometry
What is the value of?
As with all trigonometry problems, begin by considering how you could rearrange the question. They often have hidden easy ways out. So begin by noticing:
Now, you can treatlike it is any standard denominator. Therefore:
Combine your fractions and get:
Now, from our trig identities, we know that, so we can say:
Now, for our triangle, theis. Therefore,
Example Question #21 :Sine
Solve for:
if
Recall that the standardtriangle, in radians, looks like:
Since, you can tell that.
Therefore, you can say thatmust equal:
Solving for, you get: