Question

If sintheta equal to cos theta find the value of theta

Answer 1

sinФ = cosФ 
then cos(90-Ф)=cosФ
so cosФ gets cancelled
so 90=2Ф
then Ф=90/2
which is Ф=45°

Answer 2

sin∅=cos∅----------(i)
we know that.
sin∅=cos(90°-∅)
   putting value of sin∅ in eq (i)
cos(90°-∅)=cos∅
90°-∅=cos∅/cos
90°-∅=∅
90°=∅+∅
90°=2∅
90°/2=∅
45°=∅
∅=45°