Trigonometry-Doubt

Question

$1)$What is the value of $\sin 15^{o}$

$\sin 15^{o}=\sin \left ( 60^{o}-45^{o} \right )$

                  $=\sin 60^{o}.\cos 45^{o}-\cos 60^{o}.\sin 45^{o}$

                  $=\left ( \frac{\sqrt{3}}{2} \right ).\left ( \frac{1}{\sqrt{2}} \right )-\left ( \frac{1}{2} \right ).\left ( \frac{1}{\sqrt{2}} \right )$

                  $=\frac{\sqrt{3}-1}{2\sqrt{2}}$
$=\frac{\sqrt{3}-1}{2\sqrt{2}}=0.258$    
Is it correct?

$2)$ $\sin 80^{o}$ value=_____________

Is it possible to do?

Comments

Do you know any two numbers for which you know their sin values and adding/subtracting them gives 80?

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But $\sin18^{o}$ value possible. rt??

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yes because 18 is connected to 90.

https://www.math-only-math.com/exact-value-of-sin-18-degree.html