Question

O valor de sen 15° é igual a:

a) raiz de 2 + raiz de 6.
b) raiz de 2 + raiz de 6 / 2.
c) raiz de 2 - raiz de 6 / 2.
d) raiz de 2 + raiz de 6 / 4.
e) raiz de 2 + raiz de 6 / 2.​

Answer 1

Explicação passo-a-passo:

$\sf sen~(a-b)=sen~a\cdot cos~b-sen~b\cdot cos~a$

$\sf sen~(60^{\circ}-45^{\circ})=sen~60^{\circ}\cdot cos~45^{\circ}-sen~45^{\circ}\cdot cos~60^{\circ}$

$\sf sen~15^{\circ}=\dfrac{\sqrt{3}}{2}\cdot\dfrac{\sqrt{2}}{2}-\dfrac{\sqrt{2}}{2}\cdot\dfrac{1}{2}$

$\sf sen~15^{\circ}=\dfrac{\sqrt{6}}{4}-\dfrac{\sqrt{2}}{4}$

$\sf \red{sen~15^{\circ}=\dfrac{\sqrt{6}-\sqrt{2}}{4}}$

Answer 2

B



Espero ter ajudado