The range of y=asinx+b is {y| -1 ≤ y ≤ 4, yeR}.

Question

If a is positive, then the value of b is:
a) 3/2
b) -1
c) 4
d) 5/2

How do I solve this question?

Answer 1

max value = a + b
min value = -a + b
so
b-a = 1
b+a = 4
---------
2 b = 5