# Thread: Ti Nspire Cas help

1. ## Ti Nspire Cas help

This is the question

Find the exact value of sin( X + B ) if sin X = 3/5 and sin B = 5/13. with X in Quadrant 2 and B in quandrant 1

Can figure out most things but not this.

Is there a way to input this in the TI Nspire CAs calculator, and if so, how.

Thanks the test is in two days.

2. ## Re: Ti Nspire Cas help

Originally Posted by michellia
This is the question
Find the exact value of sin( X + B ) if sin X = 3/5 and sin B = 5/13. with X in Quadrant 2 and B in quandrant 1
Is there a way to input this in the TI Nspire CAs calculator, and if so, how.
$\sin(X+B)=\sin(X)\cos(B)+\sin(B)\cos(X)$

3. ## Re: Ti Nspire Cas help

Thank you

How do I enter that into the ti nspire cas and get the answer -63/65

4. ## Re: Ti Nspire Cas help

You aren't going to magically get your CAS to do every bit of work for you.

You have been told \displaystyle \begin{align*} \sin{(X + B)} = \sin{(X)}\cos{(B)} + \cos{(X)}\sin{(B)} \end{align*}.

You already have \displaystyle \begin{align*} \sin{(X)} \end{align*} and \displaystyle \begin{align*} \sin{(B)} \end{align*}, so the things that YOU must do:

1. Find \displaystyle \begin{align*} \cos{(X)} \end{align*} and \displaystyle \begin{align*} \cos{(B)} \end{align*}. The CAS will not do this for you, unless you at least write down a method to go from sines to cosines and then have the CAS do the calculations YOU find.

2. Have the CAS perform the multiplications if you really can't multiply things by hand.

The CAS calculator can not think. So you must!