Sums & Differences of Angles - Trig (1 Viewer)

[Gigacube]

If and

Find the exact value of:


All I have done is drawn 2 right angled triangles & labelled each side. Not sure what to do next. :/

 

[jnney]

Expand the sin (x+y) and sub in the values of sinx and cos y =P

 

[SpiralFlex]

Let's draw two triangles!

Label the angles and the sides.

By Pythagoras, you will see the missing side of the first triangle is and the second triangle is








Now.

 

[Gigacube]

Thanks Jnney & Spi! I owe you both rep!

 

[SpiralFlex]

Sorry in a rush today, go here if it's unclear:

Expand the sin (x+y) and sub in the values of sinx and cos y =P

I owe you rep for helping too.

 

[Gigacube]

Sorry in a rush today, go here if it's unclear: View attachment 22907

You explained it wonderfully Spi! I now understand it. Thanks for scanning it too.

 

[jnney]

oh CRAP IM SORRY ==
edit : 'sub in sin x, sin y, cos x , cos y' SORRY!

*humiliation* haha.

 

[SpiralFlex]

oh CRAP IM SORRY ==
edit : 'sub in sin x, sin y, cos x , cos y' SORRY!

*humiliation* haha.

But you were right?

 

[Gigacube]

oh CRAP IM SORRY ==
edit : 'sub in sin x, sin y, cos x , cos y' SORRY!

*humiliation* haha.

Aww, don't feel humiliated. You helped too.

 

[jnney]

Hehe okay, thanks guys!