I don't know if this is the right place to post but I've been having trouble finding anywhere that can help me, nothing on the TI website. So I've recently got the TI-Nspire CX and, whilst the Normal Trig functions work fine, I can't seem to get the inverses to work. My angles are set to degrees and Real or Complex is set to Rectangular. I'm probably being daft but can someone help?
I suppose it's a little late to answer this, but…
The way TI does it, the inverse trig functions are only defined between -1 and 1. Try that and see if it works.
(∂²Ψ)/(∂x²) = -(2m(V(x)-E)Ψ/( ℏ²Ψ)
It still doesn't work. I just tried cos^-1 (0.5) and it gave me 1.0472