Answer:
y = 4cosx
Step-by-step explanation:
Since we have cosx lying between -1 and 1, we have
y =4cosx lying between 4(-1) and 4(1)
i.e. maximum value is 4.
II option is incorrect because cos4x has maximum value only as 1.
III option is also incorrect because cos(x)+4 has maximum as 1+4=5
IV option is also incorrect because cos(x+4) has maximum as 1
As a result we have out of 4 options given only I option satisfies the condition that the function has a maximum value of 4.
