HELP PLEASE

sin[2arc cos (-3/5)]

please show all the procedure

Question

HELP PLEASE

sin[2arc cos (-3/5)]

please show all the procedure

alekos · Answer

have they given you an answer?

anonymous · Answer

yes is $$-\frac{ 24 }{ 25 }$$ but I don't know how to get there

anonymous · Answer

Okay. So when solving its quite simple...

You just must know how to plug into the calculator

So the answer is:

$$-\frac{ 24 }{ 25 }$$

anonymous · Answer

Hope this helped! Have a great day!

Also a medal would be much appreciated! Just click best response next to my answer. Thank You!

@nicolepenafielm

anonymous · Answer

I need to solve this without the use of a calculator, thats why I am asking for help

alekos · Answer

let me help you because I just did it without a calculator

anonymous · Answer

thank you so much!

alekos · Answer

start with the expression inside the square brackets and let that equal $$\theta $$


$$2arcos(-3/5) $$

alekos · Answer

so now we have 

$$2arcos(-3/5) = \theta $$

alekos · Answer

therefore 

$$arcos(-3/5) = \theta/2$$

alekos · Answer

so $$\cos(\theta/2) = -3/5$$

alekos · Answer

Now using a triangle we have the following...........|dw:1447863272676:dw|