







A trig identity 
20130104 

From Tehmas: Prove sinC+sinD=2sin(C+D/2)cos(CD/2) Answered by Harley Weston. 





2 + f(x) and f(x) + 2 
20111121 

From Beth: Do you do y=2+f(x) the same way as if the 2 came after the equation such as y=f(x) +2 when graphing? Answered by Penny Nom. 





Reflection in the line y = x 
20100721 

From tousif: Find the 2 x 2 matrix which represents a reflection in the line y = x?
Please help.... Answered by Penny Nom. 





The graph of f(x)=1/x 2 
20091129 

From Kapilan: Please answer the following question:
Sketch the graph of f(x)=1/x 2 Answered by Harley Weston. 





Transformations 
20090204 

From Vickie: Hello,
My daughter had a question on her
Week By Week about transformations and I can't remember what transformations
will result in proportional figures. If a transformation looks like it is smaller
what is that called? Also if the figure looks bigger what is that called?
Vickie Answered by Robert Dawson. 





Transformations and compositions 
20071129 

From mary: Is there any possible relationship between composite functions and the concept of function transformations? Answered by Harley Weston. 





A rotated rectangle 
20070416 

From Graham: There is a circle inside which from the centre to the top is a rectangle. Size is unimportant.
If I the rectangle is at 0 degrees and I know the coordinates of the 4 corners I can do a check to see
whether a given point x,y is inside the rectangle or not.
Question : If the rectangle is rotated by 50 degrees how do I check then as the lines of the rectangle are not
perfectly straight with regards to x and y ie at 0 degrees x changes but y is constant and vice versa.
At 50 degrees x and y change together. Answered by Penny Nom. 





Prove that a rhombus' diagonals are perpendicular 
20051002 

From Tania: How do you prove that a rhombus' diagonals are perpendicular using the 2 column proof method? Answered by Walter Whiteley. 





A torus and a sphere 
20050327 

From Tony: Is it possible to shrink a torus into a sphere? Answered by Andrei Volodin and Penny Nom. 





A sequence of transformations 
20050103 

From Abraham: Please go to this web site and look at number 31.
http://www.nysedregents.org/testing/mathre/matharch/mathbtestau02.pdf
That is the New York state education web site.
Can you tell me if my answer would be marked correct? My answer was Transformation of 4,3 (T 4,3) followed by a reflection in the xaxis.If I graphed the question and wrote that, would I get full credit Answered by Harley Weston. 





Transformations of pattern blocks 
20030206 

From Cheryl: I am trying to help my 8th grade son with Transformations  use of patttern blocks. He has to trace a figure and reflect it across the xaxis, which I can do, but then it indicates include ordered pairs  that confuses me. Answered by Penny Nom. 





Polar coordinates 
20000224 

From Tran Trung: How do I convert r = 2/(2sin(theta)  3cos(theta)) to rectangular and x^{2} + y^{2} 2y = 0 to polar form? Answered by Harley Weston. 





Shapepreserving transformations 
19990504 

From J McAndrew: A shape preserves its shape if a rotation, translation or scaling is performed on it. Are these the only continuous transformations which have this property? These transformations if performed on the parts and then summed have the same effect as the transformation being applied to the whole; are these linear transformations? Who, and what area of mathematics has classified all transformations of this type completely? Answered by Chris Fisher. 

