## Search found 6 matches

Tue Oct 05, 2010 3:34 pm
Forum: Matrix (Linear) Algebra
Topic: Proof:Show that BAB^-1 is invertible
Replies: 1
Views: 3990

### Proof:Show that BAB^-1 is invertible

Let A and B be any invertible matrix. Show that the matrix BAB^-1 is invertible. What is its inverse?
Mon Apr 19, 2010 9:59 pm
Forum: Calculus
Topic: Optimization Problem: Rain Gutter
Replies: 1
Views: 4132

### Optimization Problem: Rain Gutter

Hey there Purplemath! I need some help setting up the problem: A rain gutter is to be constructed from a long 30 cm wide sheet of metal by bending two sides upwards at and angle of theta so that each of the sides and bottom is 10 cm wide. Determine the angle theta so that the cross-sectional area of...
Wed Mar 17, 2010 11:00 pm
Forum: Calculus
Topic: Related Rates: A plane, 40 mi from airport, is flying at
Replies: 2
Views: 3643

### Re: Related Rates: A plane, 40 mi from airport, is flying at

Thank you, this helped greatly.
Wed Mar 17, 2010 8:16 am
Forum: Calculus
Topic: Related Rates: A plane, 40 mi from airport, is flying at
Replies: 2
Views: 3643

### Related Rates: A plane, 40 mi from airport, is flying at

Need some help setting up the following problem:

A plane is 40 miles (horizontally away from an airport) flying at a constant altitude of 4 miles. The radar at the airport determines that the distance from the plane to the radar dish is changing at 240 mph. Determine the speed of the plane.
Sun Mar 29, 2009 2:07 am
Forum: Beginning Algebra
Topic: Need help with Complex Fraction
Replies: 3
Views: 2969

### Re: Need help with Complex Fraction

Thanks for the quick reply!!! I think the reason I was confused with factoring the denominator is because my book does not refer to the rational roots test in prior sections, so I would never had known how to factor it anyway. Thus far it has only demonstrated factoring by common monomial, special p...
Sat Mar 28, 2009 10:28 pm
Forum: Beginning Algebra
Topic: Need help with Complex Fraction
Replies: 3
Views: 2969

### Need help with Complex Fraction

Help me finish this problem....Cant factor by grouping, what other method?