oblicz wartość wyrażenia wals: sinα−cosα=1/3 oblicz (sinα)⁴+(cosα)⁴

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Mariusz: sin⁴(α)+cos⁴(α)=(sin²(α)+cos²(α))²−2sin²(α)cos²(α)

	1
sin4(α)+cos4(α)=1−		sin2(2α)
	2

(sin(α)−cos(α))²=sin²(α)−2sin(α)cos(α)+cos²(α) (sin(α)−cos(α))²=1−sin(2α)

1
	=1−sin(2α)
9

	8
sin(2α)=
	9

	1		64
sin4(α)+cos4(α)=1−		*
	2		81

	32
sin4(α)+cos4(α)=1−
	81

	49
sin4(α)+cos4(α)=
	81