Question

examine the minimum and maximum value of cosx+cosy+cos(x+y)​

Answer 1

The maximum value of cosx+cosy+cos(x+y)​ = 3 and minimum value = -1

Step-by-step explanation:

We know that the cos function attains its minimum value as -1 at $\pi$radians.

• So, x = y = $\pi$

• x+y = $2\pi$ Now, we can write as;

•  $cos(x+y)=cos 2\pi= 1$
• This is the min value of cos(x+y).

Thus, the minimum value of cos x + cos y + cos (x+y) = -1 + (-1 )+1=-1

Also, we know that cos function attains its max value 1 at 0 radians.

so,  x = y = 0

• x+y = 0

Hence, the maximum value of cos x + cos y + cos (x+y) = 1 + (1 )+1=3

Thus, the maximum value of cos x + cos y + cos (x+y) = 3 and minimum value = -1

Answer 2

Answer:

-3/2

Step-by-step explanation:

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