What is the exact value of cos(225)cos(75)

Step-by-step explanation:

To find:

Now, angle lies in third quadrant in which is negative

So,

We know that

So,

To find:

We know that angle lies in first quadrant in which is positive. Also,

So,

We will use formula:

Here,

Therefore,

step-by-step explanation:

we can use this expression to calculate the energy gain as a particle moves with a field or the energy loss as it moves against it. (note that it is also used to define the electron-volt, a unit of energy equal to that gained by an electron as it falls through a pd of 1 v, i.e. w = 1 ev = 1.6 10-19 c 1 v = 1.6 10-19j).in fact this expression is really nothing more than the statement that potential is the potential energy per unit charge. in this case, v= w/qis simply stating that the change in potential energy(or work done) per unit charge is equal to the change in potential (or potential difference), v.student questions: uniform electric fields2electron beamcathode+5 kvanode0 v