Question

Is cos x+sin x=√2 then what is sin 3x?

Answer 1

Answer:

as given that cos x +sin x=√2

further after dividing above both side by √2

we get 1/√2cos x + sin x (1/√2)=1 (

as we know sinxcos y +cosxsin y =sinx+y

so applying this in above equation

we get sin(x+π\4) =1

so so the principal value will be

x+π\4=π\2 (as sin(π\2)=1)

so x=45° ans.