Question

найдите область значения функции y=-3+4cos2x

Answer 1

-1<=сos2x<=1

-4<=4cos2x<=4

-7<=-3+4cos2x<=1

[-7;1]

Answer 2

-1 <= cos 2x <= 1

-4 <= 4cos2x <= 4

-7 <= -3+4cos2x <= 1

y ∈ [-7; 1]