Can someone explain a math question?

Question

mtalhahassan2 · Answer

attachment

mtalhahassan2 · Answer

Can someone explain how they are getting Sin 75?

mtalhahassan2 · Answer

@Astrophysics

astrophysics · Answer

Looks they used the law of sines

mtalhahassan2 · Answer

can you please explain that to me

astrophysics · Answer

I would be willing to go through it, but I'm a bit busy right now, if you still need help after I can go through it with you.

mtalhahassan2 · Answer

@Astrophysics i have a test tomorrow

mtalhahassan2 · Answer

just explain the sin 75 part

mathmale · Answer

45+30=75, right?

mtalhahassan2 · Answer

yes

mathmale · Answer

We've broken up 75 degrees into two composite parts.
The reason for using 45 and 30 degrees is that both have easily memorized sine and cosine values.

mathmale · Answer

The sum formula for the sine function (that is, the formula for the sum of two angles x and y) is

sin (x+y) = sin x cos y + cos x sin y.

mathmale · Answer

Plugging in the appropriate x and y values and simplifying should give you the sine of 75 degrees.

mathmale · Answer

Hints:
sin 45 = 1/Sqrt(2)
cos 45 = 1 / Sqrt(2)
sin 30 = 1/2
Cos 30 = Sqrt(3) divided by 2

mathmale · Answer

I need to get off the 'Net.  Hope this math info is helpful to you.

mtalhahassan2 · Answer

@mathmale its help a lot and thnx aloy

mathmale · Answer

I'm very glad that our discussion has helped you.