|   | 1 |  initial version  | 
The parameter  locals should be a dictionary not the set {False}:
sage: var('y')
y
sage: f = sage_eval(str(input("What is the function:" )), locals = {'y': y})
What is the function:cos(y)
sage: integral(f,y,0,16)
sin(16)
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.