Question

sin theta = sqrt 2/2 which could not be the value of theta?
225 degrees
45 degrees
135 degrees
405 degrees

Answer 1

Tell what cos and sin of 45 equal to ?

Answer 2

1/sqrt2?

Answer 3

yes, but you can't have a radical in the denominator.

Answer 4

So, you would multiply top and bottom times √2, and you get, √2 / 2 .

Answer 5

Ok, now, lets explore the other options.

sin 225 = sin (180+45)=sin 180 cos 45 + cos 180 sin 45 = 0 (√2 / 2) + 1 (√2 / 2) = √2 / 2

So, option A works too.

sin 135 = sin (180-45) = sin 180 cos 45 - cos 180 sin 45 = 0 (√2 / 2) - 1 (√2 / 2) =
-√2 / 2

So, C doesn't work.

sin 405 = sin (360 +45) = sin 360 cos 45 + cos 360 sin 45 = 0 (√2 / 2) + 1 (√2 / 2) =√2 /

So option D works..

So options A B D work, option C doesn't.

\(\LARGE\color{black}{ \bf :) }\)

Answer 6

Thanks a ton! :D

Answer 7

You welcome !