Question

Prove that 1 + 10 square 45 minus am divided by 1 minus 10 square 45 minus A is equals to cos square A

Answer 1

i don,t know this answer

Answer 2

If A = 45°, then also (90° – A) = 45°, and therefore

sin 45° = cos 45°

Squaring

sin2 45° = cos2 45°

However, it was found earlier that for any angle A

sin2A + cos2A = 1

Therefore

2 sin2 45° = 1

sin2 45° = 1/2

and if √ means "square root of"

sin 45° = √(1/2)

Pushing a button on your calculator gives

sin 45° = 0.707107... = cos 45°Another way, slightly more transparent, is to write

sin2 45° = 1/2 = 2/4

sin 45° = √2/√4 = √2/2The square root of 2 is 1.4142135..., dividing it in two recovers 0.707107 as before.