Question

sin α+sin^2α=1,则cos^2 α+cos^6 α+cos^8α=

sin α+sin^2α=1,则cos^2 α+cos^6 α+cos^8α=多少？，求详细过程，谢谢！

Answer 1

sin α+sin^2α=1，cos^2α+sin^2α=1，由此两式可知sin α=cos^2α，则所求式可化为sin α+sin^3α+sin^4α，提取公因式后该式=sin α+sin^2α(sin α+sin^2α)=sin α+sin^2α=1。 纯手打，望采纳。