I am really stuck in this question. if someone could help me, that'd be awesome.
Solve the equation 2cos^2x + cosx-3=0, where -pi is less than or equal to x, which is less than or equal to +pi. Then make a general solution for that equation.
I am just so clueless with math in general.
Even factoring the equation is confusing me.
Does 2cos^2x +cosx -3 Factor out to be: (2cosx+3)(Cosx-2) or does it factor out to be (cosx-1)(Cosx+3)
Because depending on whether you put the "-2" in the same brackets as the Coefficient of 2 (Ie. [2cosx-2] or [2cosx-3]) It will factor out differently.
If someone could help me with the whole equation in general. that'd help. thank you!
You can always use the quadratic formula on a quadratic equation, sometimes it is difficult to factor them straight out as you have experienced. bigwave's solution is excellent but sometimes a bit tricky and time consuming.
The real difference is not alot, the quadratic formula solves the equation straight away where factoring is just a step in the solving process.
well agreeing with pickslides this is where the quadradic formula would be best
however this did factor
set both factors to 0 and solve
in this case on (cos(x)- 1) would solve the other was undefined
ussually tho all factors will solve.
as mentioned factoring can be tricky I just happen to see it off hand
which ussually is not the case when one is has not done it a lot
hope i didn't cause any confusion...
They are factors.
these 2 are incorrect
this one is correct, I think you are asking how do you know which ones are correct?
Read this to get some backgorund
Cross-Multiplication Method