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Solve the following inequality: 2x^2 < x+3

2x 2 &lt; x+3, 2x 2 - x - 3 &lt; 0, (2x - 3) (x + 1) &lt; 0, Positive quadratic. Roots: x = -1 and x = 3/2, Therefore, x takes values greater than -1 and less than 3/2.
OM
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What is the polar form of the equation: x^2+y^2 =xy+1

Using Pythagoras, x 2 + y 2 = r 2 .Using basic trigonometry, x = rsinθ and y = rcosθ. xy + 1 = r 2 sinθcosθ + 1 = (1/2)r 2 sin2θ + 1 Subbing in both halves and doubling gives:2r 2 = r 2 sin2θ + 2 -&gt; r 2 (...
HW
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Give the general solution to y'' - 3y' + 2y = 4x

note: y' is often written as dy/dx, this doesn't change the question at all so no need to worry. Same for y'' and d 2 y/dx 2 .All second-order differential equations that don't have 0 on the right hand side ...
DS
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Let A, B and C be nxn matrices such that A=BC-CB. Show that the trace of A (denoted Tr(A)) is 0, where the trace of an nxn matrix is defined as the sum of the entries along the leading diagonal.

This is the type of question which requires some out of the box thinking. A sketch is presented below: We start by defining A = (a ij ), B = (b ij ) and C = (c ij ). We then use the definition of matrix mult...
DG
4259 Views

Express sin(5theta) in terms of sin(theta) and powers of sin(theta) only.

Consider the expression (cos(theta) + i*sin(theta)) 5 . (Where theta a real parameter).By De Moirve's theorem, we know this expression is equivalent to cos(5theta) + i sin(5theta).We can also apply the binom...
PF
6101 Views