Show that 
Using sin(A+B) = sinA × cosB + cosA × sinB
⇒ |A| = sin10° × cos80° + cos10° x sin80°
|A| = sin(10 + 80)°
|A| = sin90°
|A| = 1
Hence Proved
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Generated by AI. May contain inaccuracies — always verify with your textbook.
