Mathematics
8 Online
OpenStudy (anonymous):
Find the general solution:
Problem in the comments, will FAN and MEDAL
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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
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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
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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?
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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):
\[\sin(x)=-\frac{1}{2}\]
\[x=\frac{7\pi}{6}+2k\pi,x=\frac{11\pi}{6}+2k\pi\]
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OpenStudy (anonymous):
Thank you both @satellite73 and @misty1212
OpenStudy (anonymous):
yw
OpenStudy (misty1212):
\[\color\magenta\heartsuit\]