If sin 21° =x , then sec 21° – sin 69° is equal toy

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sin 21° =	x
	y

cos 21° = √1 - sin² 21°

∴ sec 21° =	y
	√y² - x²

∴ sec 21° – sin 69°
= sec 21° – sin (90° – 21°)
= sec 21° – cos 21°

=		y	-	√y² - x²
		√y² - x²		y

=		y² - (y² - x²)	-	x²
		y√y² - x²		y√y² - x²