BuyFind

Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071
BuyFind

Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

Solutions

Chapter 1.1, Problem 80E

(a)

To determine

To identify: the sign of expression a .

Expert Solution

Answer to Problem 80E

  a<0

Explanation of Solution

Given information:

Three real numbers a,b,c such that a>0,b<0 , and c<0 .

Calculation:

Consider the given expression.

  a

Now, a>0

So, sign of a can be determined as shown:

  (+)=()

So, a<0 .

(b)

To determine

To identify: the sign of expression b .

Expert Solution

Answer to Problem 80E

  b>0

Explanation of Solution

Given information:

Three real numbers a,b,c such that a>0,b<0 , and c<0 .

Calculation:

Consider the given expression.

  b

Now, b<0

So, sign of b can be determined as shown:

  ()=(+)

So, b>0 .

(c)

To determine

To identify: the sign of expression bc .

Expert Solution

Answer to Problem 80E

  bc>0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Consider the given expression.

  bc

Now, a>0,b<0 and c<0 .

So, sign of bc can be determined as shown:

  ()()=(+)

So, bc>0 .

(d)

To determine

To identify: the sign of expression ab .

Expert Solution

Answer to Problem 80E

  ab>0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Now, a>0,b<0 and c<0 .

So, sign of ab can be determined as shown:

  ((+)())=((+)(+))=(+)

So, ab>0 .

(e)

To determine

To identify: the sign of expression ca .

Expert Solution

Answer to Problem 80E

  ca<0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Consider the given expression.

  ca

Now, a>0,b<0 and c<0 .

So, sign of ca can be determined as shown:

  (())=()(+)=()

So, ca<0 .

(f)

To determine

To identify: the sign of expression a+bc .

Expert Solution

Answer to Problem 80E

  a+bc>0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Consider the given expression.

  a+bc

Now, a>0,b<0 and c<0 .

So, sign of a+bc can be determined as shown:

  (+)+()()=(+)+(+)=(+)

So, a+bc>0 .

(g)

To determine

To identify: the sign of expression ab+ac .

Expert Solution

Answer to Problem 80E

  ab+ac<0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Consider the given expression.

  ab+ac

Now, a>0,b<0 and c<0 .

So, sign of ab+ac can be determined as shown:

  (+)()+(+)()=()+()=()

So, ab+ac<0 .

(h)

To determine

To identify: the sign of expression abc .

Expert Solution

Answer to Problem 80E

  abc<0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Consider the given expression.

  abc

Now, a>0,b<0 and c<0 .

So, sign of abc can be determined as shown:

  (+)()()=()(+)(+)=()

So, abc<0 .

(i)

To determine

To identify: the sign of expression ab2 .

Expert Solution

Answer to Problem 80E

  ab2>0

Explanation of Solution

Given information:

Three real numbers a,b,c such that, a>0,b<0 and c<0 .

Calculation:

Consider the given expression.

  ab2

Now, a>0,b<0 and c<0 .

So, sign of ab2 can be determined as shown:

  (+)()2=(+)(+)=(+)

So, ab2>0 .

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