SOLUTION: 2 cos^2 theta-13 cos theta = -6
We are asked to find:
a) all degree solutions and (let k be any integer)
b) 0 degree<theta<360 degrees
I have no idea how to set up thes
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Question 960544: 2 cos^2 theta-13 cos theta = -6
We are asked to find:
a) all degree solutions and (let k be any integer)
b) 0 degree
I have no idea how to set up these problems (we are not supposed to use a calculator) and how the degrees are found.
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
2 cos^2 theta-13 cos theta = -6
We are asked to find:
a) all degree solutions and (let k be any integer)
b) 0 degree I have no idea how to set up these problems (we are not supposed to use a calculator) and how the degrees are found.
***
use x for theta
2cos^2(x)-13cosx=-6
2cos^2(x)-13cosx+6=0
..
let u=cosx
u^2=cos^2(x)
..
2u^2-13u+6=0
(2u-1)(u-6)=0
..
2u-1=0
u=1/2=cosx
x=60˚+360k, 300˚+360k, k=any integer
..
u-6=0
u=6≠cosx(no solution, (-1 ≤ cosx ≤ 1)
note: I don't understand what b) is asking.
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