Find the value of 3Sin2 20® - 2Tan2 45® + 2Sin2 70®

1.	Find the value of 3Sin2 20® - 2Tan2 45® + 2Sin2 70®
Answer» 3sin²20°-2tan²45°+2sin²70°=3sin²20°-2×(tan45°)²+2{sin(90°×1)-20°}²=3sin²20°-2×(1)²+2cos²20°=3sin²20°+ 2cos²20°

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