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Mathematics 8 Online
OpenStudy (anonymous):

Find the general solution: Problem in the comments, will FAN and MEDAL

OpenStudy (anonymous):

\[2\cos^2 x=2+sinx\]

OpenStudy (misty1212):

HI!!

OpenStudy (misty1212):

rewrite the left hand side a \[2(1-\sin^2(x)\] then you will have a quadratic equation in sine

OpenStudy (anonymous):

Kay, I wrote that

OpenStudy (misty1212):

then multiply out

OpenStudy (misty1212):

and set it equal to zero

OpenStudy (misty1212):

\[2-2\sin^2(x)=2+\sin(x)\] \[2\sin^2(x)-\sin(x)=0\]

OpenStudy (anonymous):

wouldnt it be a plus on the second line?

OpenStudy (misty1212):

yes i guess it would wouldn't it

OpenStudy (misty1212):

\[2\sin^2(x)+\sin(x)=0\\ \sin(x)(2\sin(x)+1)=0\] that's better

OpenStudy (anonymous):

how'd you get that second line? @misty1212

OpenStudy (misty1212):

factored out the sine

OpenStudy (anonymous):

what's next

OpenStudy (misty1212):

set each factor equal to zero and solve

OpenStudy (anonymous):

sinx=0 and sinx=-1/2?

OpenStudy (misty1212):

yes

OpenStudy (misty1212):

then solve for x

OpenStudy (anonymous):

Do you know how I would write the solutions in the general form format? @misty1212

OpenStudy (anonymous):

\[\sin(x)=0,x=0,\pi,2\pi,3\pi,...\] or \[x=k\pi, k\in \mathbb{Z}\]

OpenStudy (anonymous):

\[\sin(x)=-\frac{1}{2}\] \[x=\frac{7\pi}{6}+2k\pi,x=\frac{11\pi}{6}+2k\pi\]

OpenStudy (anonymous):

Thank you both @satellite73 and @misty1212

OpenStudy (anonymous):

yw

OpenStudy (misty1212):

\[\color\magenta\heartsuit\]

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