cos(a+b)=m(cos(a-b) then tan a=?

1 answer

1. Expand both sides using sum of angles formula:
   cos(a+b)=cos(a)cos(b)-sin(a)sin(b)
   cos(a-b)=cos(a)cos(b)+sin(a)sin(b)
   
   Divide by cos(a) on both sides and solve for tan(a) to get:
   
   tan(a)=cot(b)*(1-m)/(1+m)
   
   Check me.

   Answer ID
   539491

   Created
   April 30, 2011 1:43pm UTC

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   URL
   https://questions.llc/answers/539491