Which of the following is equivalent to [tex]\sin \left(30^{\circ}\right)[/tex]?

A) [tex]\cos \left(90^{\circ}\right)[/tex]
B) [tex]\cos \left(30^{\circ}\right)[/tex]
C) [tex]\sin \left(60^{\circ}\right)[/tex]
D) [tex]\cos \left(60^{\circ}\right)[/tex]



Answer :

To determine which of the given options is equivalent to [tex]\(\sin(30^\circ)\)[/tex], we will evaluate the trigonometric functions for the specific angles involved.

1. Evaluate [tex]\(\sin(30^\circ)\)[/tex]:
[tex]\[ \sin(30^\circ) = 0.49999999999999994 \][/tex]

2. Evaluate [tex]\(\cos(90^\circ)\)[/tex]:
[tex]\[ \cos(90^\circ) = 6.123233995736766 \times 10^{-17} \][/tex]

3. Evaluate [tex]\(\cos(30^\circ)\)[/tex]:
[tex]\[ \cos(30^\circ) = 0.8660254037844387 \][/tex]

4. Evaluate [tex]\(\sin(60^\circ)\)[/tex]:
[tex]\[ \sin(60^\circ) = 0.8660254037844386 \][/tex]

5. Evaluate [tex]\(\cos(60^\circ)\)[/tex]:
[tex]\[ \cos(60^\circ) = 0.5 \][/tex]

We see that:
- [tex]\(\cos(90^\circ) = 6.123233995736766 \times 10^{-17}\)[/tex], which is extremely close to 0.
- [tex]\(\cos(30^\circ) = 0.8660254037844387\)[/tex], which is not equal to [tex]\(\sin(30^\circ)\)[/tex].
- [tex]\(\sin(60^\circ) = 0.8660254037844386\)[/tex], which is not equal to [tex]\(\sin(30^\circ)\)[/tex].
- [tex]\(\cos(60^\circ) = 0.5\)[/tex], which is indeed very close to [tex]\(\sin(30^\circ)\)[/tex].

Therefore, the function that is equivalent to [tex]\(\sin(30^\circ)\)[/tex] is:
[tex]\[ \cos(60^\circ) \][/tex]

Thus, the correct answer is:
[tex]\[ \boxed{\text{D}} \][/tex]