Top answers


Find the square root of complex number 3 + 4i

Strategy: write down an equation satisfied by the square root, and solve it algebraically. Method: square root x+iy satisfies (x+iy) 2 = 3 + 4i. Expand: x 2 -y 2 +2xyi = 3+4i. Comparing coefficients gives: x...
JS
29107 Views

Show that cosh^2(x)-sinh^2(x)=1

In exponential form, sinh^2(x)=1/4(e^2x+e^-2x-2), cosh^2(x)=1/4(e^2x+e^-2x+2). Therefore cosh^2(x)-sinh^2(x)=1/4(2-(-2))=4/4=1, as required.
TD
11000 Views

Why is the argument of a+bi equal to arctan(b/a)?

Think about the point a+bi on the complex plane. Specifically, a is how far along the x (real) axis, and b is how far up the y (imaginary) axis the point is. If you draw a line connecting the origin and the ...
MS
15944 Views

Find the general solution to y''+2y'-3y=x

y''=d 2 y/dx 2 , y'=dy/dx for ease of writing First off split the full equation into th homogeneous equation and the particular function. The homogenous equatiion is when our collection of y, y', y'' are on ...
ZG
8640 Views

Find the first three non-zero terms of the Taylor series for f(x) = tan(x).

We have that the Taylor series of a function infinitely differentiable at a x = a is given by the expansion: f( x ) = f( a ) + f'( a )( x - a ) + f''( a )( x - a ) 2 /2! + f'''( a )( x - a ) 3 /3! + f (4) ( ...
AS
13079 Views