Trigonometry Help

Factor:
6cos^2(x) + 5cos(x) + 1 = 0

My mind has kinda blanked out atm, just need some refreshing.

Question

Trigonometry Help

Factor:
6cos^2(x) + 5cos(x) + 1 = 0

My mind has kinda blanked out atm, just need some refreshing.

precal · Answer

can you do this problem if cos(x) did not exist?

precal · Answer

6x^2+5x+1=0 can you factor this one?

anonymous · Answer

i keep coming out with 6x^2 + 7x + 1

anonymous · Answer

like after i factor it

anonymous · Answer

and check my answer

precal · Answer

yes take your time

anonymous · Answer

do i have to get the 5x to be just x or something first?

precal · Answer

no but you do need to keep it in mind when you factor
how do you factor?
do you do factor by grouping by breaking up the 5x?

anonymous · Answer

|dw:1404667944293:dw|

precal · Answer

ok let me show you another way to do this then you can decide which way to factor
it is known as slide and divide
do you want to learn it?

anonymous · Answer

id love to

precal · Answer

actually it won't help us here because this is not factorable

precal · Answer

so we need to use the quadratic formula

precal · Answer

can you use a graphing calculator to solve it?  we could graph it

anonymous · Answer

ahhh quadratic forumla! of course!

anonymous · Answer

alright i know exactly how to do itnow
a=6 b=5 c=1

precal · Answer

yes small problem, your x is really cos x   so when you finish set it equal to cos (x)= numbers

anonymous · Answer

yes of course, thank you so much
i totally forgot about quadratic formula

anonymous · Answer

got it, thanks agian

precal · Answer

yw anytime