I am preparing for a pre-calculus mid-term that is tomorrow afternoon. I'm working on double angle problem. We are allowed to use calculators during the test. I mostly just use mine to check my work, but I am having a slight issue with my ti n-spire cx cas. Instead of keying in the problem I'll upload a picture. Here's a brief description. When I input the problem into the graphing calculator, it just gives me back some composite function, instead of the real answer. When I input the same problem into my cheap casio calculator it actually gives back the real answer that I am expecting. Is there something that I am missing in the ti n-spire's settings? I have it set to radian mode, float 6, and auto for the calculation mode. I have played with just about every setting combination that there is and I cannot get the darn thing to give me the number that I want. We can't have two calculators during the test, and there are many advantages to the ti nspire, so I really want to use it on the test. Please advise.