Question

Show that (sin^(4)x-cos^(4)x)/(sin^(2)x-cos^(2)x)=1

Answer 1

(sin⁴x -cos⁴x)/(sin²x-cos²x)

[(sin²x-cos²x)(sin²x+cos²x) ]/(sin²x-cos²x)

=(sin²x+cos²x)

=1