f(x)=2sin(x+45度)

问题描述:

f(x)=2sin(x+45度)
若函数f(X)经过点(a,6/5) π/4<a<3π/4 求f(π/4+a)的值

函数f(X)经过点(a,6/5) ,代入原方程,得sin(a+π/4)=3/5
设a+π/4=t,π/2<t<π
则sint=3/5,cost=4/5
求f(π/4+a)=2sin(t+π/4)=2(sintcosπ/4+costsinπ/4)=7/5*(根号2)