Question

If sinA-cosA=0. Find the value of sin^4A+cos^4A.

Answer 1

Here sin^4A+cos^4A=
(sin square A + cos square A) (sin Square x - cos square x)
=1 (sin square x minus cos square x) let it be eqauation 1
we are given that Sin A minus Cos A is equal to zero
therefore
sinA is equal to Cos A
TanA is equal to 1
therefore a is equal to 45° or 225°
substituting the value of a in equation when we get.
sin square 45 degree minus cos square 45 degree =0
OR
sin square 225 degree minus cos square 225 degree
=-1/root 2 minus, (minus one by root 2)
=0