Statement :- We assume the orthagonal sequence
in Hilbert space, now
, the Fourier coefficients are given by:

Then Bessel's inequality give us:

Proof :- We assume the following equation is true

So that,
is projection of
onto the surface by the first
of the
. For any event, 
Now, by Pythagoras theorem:


Now, we can deduce that from the above equation that;

For
, we have

Hence, Proved
Answer:
-252.52
Explanation:
L = Distance between lenses = 10 cm
D = Near point = 25 cm
= Focal length of objective = 0.9 cm
= Focal length of eyepiece = 1.1 cm
Magnification of a compound microscope is given by

The angular magnification of the compound microscope is -252.52
Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
As we know that ball will reach at maximum height at
t = 3 s
now we will have

now we have


Now maximum height above ground is given as



Part b)
Height of the fence is given as



Part c)
As we know that its horizontal distance moved by the ball in 5.5 s is given as



now total time of flight is given as

so range is given as



so the distance from the fence is given as


The Greek philosopher Aristotle and the Roman Catholic Church also believed the sun revolved around the earth. In 1543, Nicolaus Copernicus<span> published a new theory stating the earth revolves around the sun. This is known as the Copernican theory.</span>
Answer:
Option B. 5 nC
Explanation:
From the question given above, the following data were obtained:
Capicitance (C) = 100 pF
Potential difference (V) = 50 V
Quantity of charge (Q) =?
Next, we shall convert 100 pF to Farad (F). This can be obtained as follow:
1 pF = 1×10¯¹² F
Therefore,
100 pF = 100 pF × 1×10¯¹² F / 1 pF
100 pF = 1×10¯¹⁰ F
Next, we shall determine the quantity of charge. This can be obtained as follow:
Capicitance (C) = 1×10¯¹⁰ F
Potential difference (V) = 50 V
Quantity of charge (Q) =?
Q = CV
Q = 1×10¯¹⁰ × 50
Q = 5×10¯⁹ C
Finally, we shall convert 5×10¯⁹ C to nano coulomb (nC). This can be obtained as follow:
1 C = 1×10⁹ nC
Therefore,
5×10¯⁹ C = 5×10¯⁹ C × 1×10⁹ nC / 1 C
5×10¯⁹ C = 5 nC
Thus, the quantity of charge is 5 nC