If tan α = 2, then the value ofsinαissin3α

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tanα = 2
∴ sec²α = 1 + tan²α = 1 + 2²
= 1 + 4 = 5

Expression =	sinα
	sin³α + cos³α

=	sinα	.	1	.	1
	cosα		cos²α		(tan³α + 1)

= tanα.sec²α.	1
	(tan³α + 1)

= 2 × 5 ×	1
	(2³ + 1)

=	10
	9