Question

Please help me with this question

Answer 1

Answer:

cos(x-30)=1/2

Step-by-step explanation:

We use the following relationship to obtain cos(x)

$sin^{2}(x) +cos^{2}(x) +1$

From that, we have that cos(x)= sqrt(1-1/4)=sqrt(3) / 4

To obtain the value of cos(x-30), lets remember the following expression:

$cos(a-b)=cos(a)*cos(b)+sin(a)*sin(b)$

Therefor, we can use that to obtain our desired function cos(x-30)

cos(x)*cos(30)+sin(x)*sin(30)

$\frac{\sqrt{3} }{2} * \frac{\sqrt{3} }{2} +\frac{-1}{2}*\frac{1}{2}$

=2/4=1/2