Tìm giá trị lớn nhất giá trị nhỏ nhất Cos(x+π/3)+ cos(x-π/3)

asked Jun 8, 2022 83.0k views

0 votes

Tìm giá trị lớn nhất giá trị nhỏ nhất
Cos(x+π/3)+ cos(x-π/3)

by Sapan

3.6k points

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3 votes

Answer:

GTLN : 1 GTNN: -1

Explanation:

Ta có:

$y=cos(x+(\pi )/(3) ) + cos(x-(\pi )/(3) ) \\ = 2.cosx.cos(\pi )/(3) \\ = cosx$

mà
$-1\leq cosx \leq 1$

Nên Max
y=1 ,
∈

Min
y = -1 ,
∈

Mateusz Pusz answered Jun 15, 2022

3.8k points

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