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Show that cos(A+45)=cos45(cosA-sinA)

1 Answer

3 votes
Hello here is a solution :
co(a+b) =cosacosb -sina sinb
cos(A+45)=cosAcos45-sinAsin45
cos45=sin45

cos(A+45)=cosAcos45-sinAcos45=cos45(cosA-sinA)
User Kyle Emmanuel
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