Question

已知x=-5,y=-1/5,求x的二次方乘x的2n次方乘(y的n次方)的二次幂

急~~~~~~~~~~

Answer 1

xy=-5*(-1/5)=1

原式=x²*x^(2n)*y^2n)
=x²*(xy)^2n
=(-5)²*1^2n
=25

Answer 2

令x=3cosθ
则y²=4(1-cos²θ)=4sin²θ
y=2sinθ
T=6sinθ+6cosθ
=6√2(√2/2sinθ+√2/2cosθ)
=6√2(sinθcosπ/4+cosθsinπ/4)
=6√2sin(θ+π/4)
sin最大=1
所以T最大值=6√2 令x=3cosθ
则y²=4(1-cos²θ)=4sin²θ
y=2sinθ
T=6sinθ+6cosθ
=6√2(√2/2sinθ+√2/2cosθ)
=6√2(sinθcosπ/4+cosθsinπ/4)
=6√2sin(θ+π/4)
sin最大=1
所以T最大值=6√2