函数y=cos^2x+sinx(—π/6≤x≤π/6)的最大值与最小值之和为?
秦亮曦回答:
f(x)=(cosx)^2+sinx
=1-(sinx)^2+sinx
=-(sinx)^2+sinx+1
=-(sinx-1/2)^2+5/4
-π/6≤x≤π/6
∴-1/2≤sinx≤1/2
∴1/4≤f(x)≤5/4
最大值与最小值之和=3/2
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函数y=cos^2x+sinx(—π/6≤x≤π/6)的最大值与最小值之和为?
秦亮曦回答:
f(x)=(cosx)^2+sinx
=1-(sinx)^2+sinx
=-(sinx)^2+sinx+1
=-(sinx-1/2)^2+5/4
-π/6≤x≤π/6
∴-1/2≤sinx≤1/2
∴1/4≤f(x)≤5/4
最大值与最小值之和=3/2