Question

tan α=2,求[(sin α+ cos α) / (sin α+ cos α)] + cos²α的值

Answer 1

[(sin α+ cos α) / (sin α+ cos α)] + cos²α

=[(tan α+ 1) / (tan α+ 1)] + 1/(tan²α+1) 【前一项的分子分母同除以cos a】

=1+1/(2²+1)

=6/5

你看看题目有没有错