110quiz3solutions - Math 110 Quiz 3 Sept. 21, 2006 Name: 1....

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Math 110 Quiz 3 Sept. 21, 2006 Name: 1. Let f ( x ) = x 2 - 5 and g ( x ) = 2 x + 6. (a) Determine the functions ( f + g )( x ), ( f - g )( x ), ( fg )( x ) and ( f g )( x ). (b) Determine ( f + g )( - 3), ( f - g )( - 3), ( fg )( - 3) and ± f g ² ( - 3). (c) Determine the domain of the functions f + g , f - g , fg , and f g . Solutions: (a) ( f + g )( x ) = f ( x ) + g ( x ) = x 2 - 5 + 2 x + 6 , ( f - g )( x ) = f ( x ) - g ( x ) = x 2 - 5 - 2 x + 6 , ( fg )( x ) = f ( x ) g ( x ) = ( x 2 - 5) 2 x + 6 , and ± f g ² ( x ) = f ( x ) g ( x ) = x 2 - 5 2 x + 6 (b) ( f + g )( - 3) = ( - 3) 2 - 5 + p 2( - 3) + 6 = 4 , ( f - g )( - 3) = ( - 3) 2 - 5 - p 2( - 3) + 6 = 4 , ( fg )( - 3) = (( - 3) 2 - 5)0 = 0 , and ± f g ² ( - 3) = 4 0 = undefined (c) To find the domain of f + g , f - g , and fg , we find the domains of f and g and take what is com- mon to both. Since the domain of f is ( -∞ , ), we only need to find the domain of g . Since we cannot take the square root of a negative number, we set 2 x + 6 0, which means
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/16/2008 for the course MATH 110 taught by Professor Carlson during the Spring '07 term at University of Arizona- Tucson.

Page1 / 2

110quiz3solutions - Math 110 Quiz 3 Sept. 21, 2006 Name: 1....

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online