|ll|lll|'s question thread

[|ll|lll|]

1. How do I solve cos(x)=sin(2x) on the ti-nspire without having to change it to the double angle formula? I have tried nsolve, but it gives an approximate answer, and only one answer, instead of all four solutions.
What does numerical solve mean too? Is there always one solution given for nsolve?

2. Prove

Any help appreciated :-)

[pi]

1. How do I solve cos(x)=sin(2x) on the ti-nspire without having to change it to the double angle formula? I have tried nsolve, but it gives an approximate answer, and only one answer, instead of all four solutions.

Chuck in a domain at the end: solve(...=...,x)|a<x<b or something like that. It will give all the solutions in that domain

[yawho]

For (2), change tan to sin/cos etc.

[Somye]

For the first one, the easiest way is to convert sin 2x to 2sinxcosx
From that, you get cos(x)-2sin(x)cos(x) = 0
Factorise and you get cos(x)(1-2sinx) = 0
Then use NFL and solve