Find-the-range-of-y-cos-2-x-3cos-x-5-

Question Number 122843 by ZiYangLee last updated on 20/Nov/20

Find the range of y = \cos^{2} x - 3 \cos x + 5

Commented by Dwaipayan Shikari last updated on 20/Nov/20

- 1 ⩽ c o s x ⩽ 1

- 3 ⩽ - 3 c o s x ⩽ 3

R a n g e y_{m i n} = - 3 + 5 + 1 = 3

y_{m a x} = 3 + 5 + 1 = 9

3 ⩽ y ⩽ 9

Commented by ZiYangLee last updated on 21/Nov/20

thanks