Question

pls answer friends .,,,,,,

Answer 1

 You must realise that 22.5 = 45/2.

cos(45)=1/√2

Using the trigonometric identify

  cos(2x)=1−2(sin(x))^2

So 

1/√2 =cos(2∗22.5)

cos(2∗22.5)=1−2(sin(22.5))^2

So 

sin(22.5)= √ ( √2-1 / √2 )

Answer 2

Hey sis , here is your answer........!!☺

❗❗____________________________________❗❗


#, We know ,⤵⤵

~, sin x/2 = +_ { √ 1 - cosx /2 }

and cos 45 = 1/√2.

So, sin ( 45/2) = { √ 1 - cos45 / 2 }

= { √ 1 - 1/√2 / 2 }

= { √ √2 - 1 / √2 / 2 }

= { √ √2 -1 / 2√2 }

= { √ 2 - √2 /4 }

= { √ 2 - √2 / 2}. Ans..☺❗❗


❗❗________________________________❗❗☺