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what does it mean if "b^2 - 4ac < 0" for a quadratic equation (eg y = a*x^2 + b*x + c)

The question comes from the quadratic equation r = (-b +- sqrt(b 2 - 4ac)/2a where r is the root or x coordinate where the line crosses the x-axsis (the y coordinate is always 0). If b 2 - 4ac &lt; 0 then to...
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Answered by Nick W. • Maths tutor
5964 Views

How do I structure an essay?

Once you have cracked the formula for doing an essay, you will start to see your grades get better and better. I always remember what I have to write by thinking of PEEL and FSL. But what do these have to do...
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Answered by Evie R. • English tutor
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A source emits yellow light (λ = 589nm) uniformly in all directions and has a power of 1W. Calculate the total number of photons emitted per second and the frequency with which they impinge on a surface area of (10^−19 m2) at a distance of 1m

First, to break down this sort of question we should read each physical unit (W(atts) in this case) as its equivalent statement. ie 1W=1Js^-1, if this is not intuitive, think of the basic equation P=E/t. (Fu...
MC
4676 Views

Describe and explain the role of inspiratory and expiratory muscles during normal breathing

The main muscle of normal quiet breathing is the diaphragmDuring Inspiration, it contracts which causes it to flatten. This increases the volume of the thoracic cavity and so the pressure decreases. This all...
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Answered by Symran D. • Biology tutor
3036 Views

In considering the process of change in the conduct of warfare in the years 1845-1991, how far can the bombing of Guernica be seen as a turning point?

It is arguable that there were other equally significant turning points in warfare, such as the advent of the aviation and the railways, the use of chemicals and the invention of the nuclear bomb; however th...
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Answered by Christy O. • History tutor
2318 Views