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Trig identities |
2007-07-30 |
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From Suzanne:
I'm a UR University Graduate (with High honours!) but not in math: I'm taking GeoTrig, Sk Learning version, and the text is poorly written. But I was flying through the material until I hit the Trig Identities. I just don't get WHY we have them, why we should know them? What good is this "theory". All that "simplying" rarely yeilds a simple-er version! Also, give me advice for how to study them.
Thanks
Suzanne
Answered by Harley Weston. |
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Using the chain rule to solve a derivative |
2007-07-29 |
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From Charles:
I need to find the derivative fo the following function.
_______________________
\/ ______________
\/ (x - 1) / (x + 2) + 1
Answered by Stephen La Rocque. |
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Permutations and combinations |
2007-07-29 |
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From Marcy:
I'm having difficulty teaching my students when to use permutations or combinations. Is there a "catchy" way to teach them that will help them to identify when to use permutations and combinations?
Answered by Penny Nom. |
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Two chords in a circle |
2007-07-29 |
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From Jerry:
Points A and C lie on the circumference of a circle. B is a point inside the circle. When produced, AB and CB meet the circumference at points E and D respectively. Prove that AB = CB, then EB = BD.
Answered by Stephen La Rocque. |
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The odds of winning a contest |
2007-07-29 |
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From Kevin:
I have been asked by a customer in Missisauga to track down some odds of
winning a contest. In this contest, the last 4 digits of the winner's
driver's license number have to match the last 4 digits of a Harley VIN
number. There are 200 people maximum allowed into the drawing, 10,000 total
possible VIN combos. Would the odds be 1:50 or something other than that?
Answered by Harley Weston. |
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Building a garage |
2007-07-29 |
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From charles:
I want to build a garage that is 24 feet 4 inches wide by 50 feet long.
can you please tell me what the length of one corner is to the other?
Answered by Penny Nom. |
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320 acre lots |
2007-07-29 |
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From melisa:
we are splitting a 320 acre parcel into five 35 acre lots with one 145 ace lot. I have the footage of each side there are eight:
5280 x 2640x2640then out1320x1320up x2640back inx1320upx1320this now would meet back to the 5280foot side i know there is a half of a square mile and 320 acres.what would the measurements be in feet for length to make a square or a rectangle to make a 35 acre lot?
Answered by Harley Weston. |
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A 20,000 gallon fuel bag |
2007-07-28 |
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From Kevin:
I have a 20,000 gallon fuel bag Length 32'x Width 29'x Height 4.2'. I need to build a containment around it. If the bag was to rupture the containment would have to hold the 20,000 gallons of fuel plus ten percent. What size would the containment have to be in order to hold the fuel.
Answered by Stephen La Rocque. |
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Equation of a perpendicular line |
2007-07-28 |
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From Marina:
Find the equation, is standard form, with all integers coefficients, of the line
perpendicular to x+3y=6 and passing through (-3,5)
Answered by Stephen La Rocque. |
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A polynomial equation |
2007-07-28 |
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From claire:
Hi
I sent this question a while ago but I think I put in the wrong email address. So here it goes again....
If 4x^3 - 6x^2 + 1 = (x-2)(x+1)Q(x) +ax+ b where Q(x) is a polynomial, find a and b.
Answered by Penny Nom. |
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Solve by substitution |
2007-07-28 |
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From Marina:
I am stuck with this substition please help.
-3x+y=1
5x+2y=-4
Answered by Penny Nom. |
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Solve y'' + y = 0 |
2007-07-28 |
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From Shih-ya:
How do you solve y’’ + y = 0
Answered by Stephen La Rocque and Harley Weston. |
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At what speed does Chuck travel? |
2007-07-27 |
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From Jessica:
Chuck and Dana agree to meet in Chicage for the weekend. Chuck travels
224 miles in the same time that Dana travels 204 miles. If Chuck's rate of travel
is 5 mph more than Dana's, and they travel the same length of time, at what speed
does Chuck travel?
Answered by Harley Weston. |
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A sequence of numbers |
2007-07-27 |
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From Shamik:
Question: A sequence of numbers is defined in the following way.
B(1) = 1
B(n) = B(n-1) + {Sum of the digits of B(n-1)} for n > 1.
B(1) = 1
B(2) = 2
B(3) = 4
B(4) = 8
B(5) = 16
B(6) = 23
B(7) = 28
B(8) = 38
B(9) = 49
::::::::: and so on ...
Is the number 123456789 a term in the given sequence?
Shamik
Answered by Claude Tardif. |
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More on the cardinality of sets |
2007-07-27 |
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From Mac:
Can you please help me to find and verify whether the following are
finite, countably infinite and uncountable ?
Answered by Harley Weston. |
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