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Given z=cosx+isinx, show cosx=1/2(z+1/z)

We first consider 1/z=(cosx+isinx)^(-1). Application of De Moivre's theorem for integer n: (cosx+isinx)^(n)=cosnx+isinnx yields the result 1/z=cosx-isinx. Addition of the two forms z and z^(-1) steers us ...

CS
9081 Views

Find the roots of the following function: f(x)= 3*(x-1)^2 - 6.

In this question, we have to find the roots of f(x) or, in other words, its zeros. This means that we have to find all of the values of x for which f(x)=0. Therefore, the first step is to write down our e...

KW
Answered by Karol W. Maths tutor
5182 Views

Given the Earth orbits the Sun at a distance of 1.49*10^11m with Me = 5.97*10^24kg and Msolar = 1.99*10^30, what is the gravitational force between the Earth and Sun?

Using F = Gm1m2/r^2 and substituting in the values, we get F = 3.57*10^22N.

AS
Answered by Aaron S. Physics tutor
2466 Views

Why does cholesterol need to be reduced and how do statins do this?

-High levels of cholesterol (especially LDL's, the 'bad' type) clog the arteries with a thick fatty substance

-This causes narrowing of the coronary arteries (which carry blood to the heart)

IP
Answered by Isobel P. Biology tutor
2943 Views

I don't understand how to solve quadratic inequalities?

Let us look at an example so we can see what is going on as we go through the method. Be cautious of just memorising the method; understanding it will make your life far easier.

Q: x+ ...

SH
Answered by Sara H. Maths tutor
3974 Views

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