a属于(0,π/4).sin(π/4-a)=3/5 求tan(2a+π/4)
问题描述:
a属于(0,π/4).sin(π/4-a)=3/5 求tan(2a+π/4)
答
a∈(0,π/4)∴ π/4-a∈(0,π/4)∵ sin(π/4-a)=3/5∴ cos(π/4-a)=4/5∴ tan(π/4-a)=3/4∴ tan[2(π/4-a)]=2tan(π/4-a)/[1-tan²(π/4-a)]=(3/2)/(1-9/16)=24/7即 tan(π/2-2a)=24/7∴ tan(2a+π/4)=tan[3...