(cos3a+cos4a+cos5a)/(sin3a+sin4a+sin5a)

Question

(cos3a+cos4a+cos5a)/(sin3a+sin4a+sin5a)

Answer 1

(2cos4acosa+cos4a)/(2sin4acosa+sin4a)=cos4a(2cosa+1)/sin4a(2cosa+1)=ctg4a