- Thread starter Albi
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Use the identity:cos(3x-π/4)=sin(x)

Can someone help me solve this equation?

\(\displaystyle sin[x] = cos[(4n+1)\frac{\pi}{2} \ - \ x]\)

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I would probably start with the cofunction identity, replacing sin(x) with cos(pi/2 - x). Then you have two equal cosines, and can consider the two conditions under which the cosines of angles can be equal: either they are coterminal, or one is coterminal with the negative of the other.cos(3x-π/4)=sin(x)

Can someone help me solve this equation?