Question

Evaluate the following:(sintheta +costheta)^2+(sintheta-costheta)^2

Answer 1

I hope this is a sufficient answer and it help you

if it help you please mark as branilist

Answer 2

(sintheta +costheta)^2+(sintheta-costheta)^2

here the identities (a+b)² and (a-b)² can be used ,

i am going to use 'a ' instead of theta

(sin²a + 2×sin a ×cos a + cos²a) + (sin²a - 2×sin a ×cos a + cos²a)

since , sin²theta + cos²theta =1 . we can write 1 in place of sin²a + cos²a

(1+ 2×sin a ×cos a ) + (1-2×sin a ×cos a)

open the brackets ,

1+ 2×sin a ×cos a  + 1 - 2×sin a ×cos a

=2 + 0

=2

hope my answer is helpful :)