Question

What are the formulae of (1) 1 + cos2x (2) 1 - cos2x​

Answer 1

Answer:

Answer:

Cos (a + b) formula is

Cos (a + b) = Cos a. cos b – Sin a. Sin b………………………..(1)

but when a is same as b then

Cos 2a = Cos a. Cos a – Sin a. Sin a

Cos 2a = Cos2a – Sin2a………………………………………..(2)

We know that

Cos2a + Sin2a = 1………………………………………………….(3)

Consider the given equation 1 + Cos 2x

1 + Cos 2x

From equation (2) we can write it as

1 + Cos 2x = 1 + Cos2x – Sin2x…………………………………(4)

From equation (3) 1 can be written as Cos2x + Sin2x. Substitute in the equation (4)

1 + Cos 2x = Cos2x + Sin2x + Cos2x – Sin2x

1 + Cos 2x = 2Cos2x

Now

1 – Cos 2x = 1 – Cos2x – Sin2x…………………………………(5)

From equation (3) 1 can be written as Cos2x + Sin2x. Substitute in the equation (5)

1 – Cos 2x = Cos2x + Sin2x – Cos2x Sin2x

1 – Cos 2x = 2 Sin2x

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Answer 2

Step-by-step explanation:

each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e. the number of protons in the nuclei of its atoms.