Question

Cos raise to power 4 subtract sin raise to power 4 os equal to

Answer 1

Answer:

${cos}^{4} x - {sin}^{4} x \\ = ( {cos}^{2} x + {sin}^{2} x)({cos}^{2} x - {sin}^{2} x) \\ = 1 \times ({cos}^{2} x - {sin}^{2} x) \\ = cos2x$

Answer 2

Answer:

that's possible answer .use trigonometric identity