(sec2 37°- cot 2 53°) tan21° tan69°-sin51°cos39° -cos 51°sin 39°
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Answer:
Value of (sec²37°-cot²53°)tan21°tan69°-sin51°cos39°-cos51°sin39°=0
Step-by-step explanation:
Value of (sec²37°-cot²53°)tan21°tan69°-sin51°cos39°-cos51°sin39°
=[sec²(90°-53°)-cot²53°]tan21°cot(90°-21°)-sin(90°-39°)cos39°-cos(90°-39°)sin39°
=(cosec²53°-cot²53°)tan21°cot21°-cos39°cos39°-sin39°sin39°
/* we know that,
i)cosec²A-cot²A = 1,
ii)tanAcotA = 1 */
= 1×1-cos²39°-sin²39°
= 1-(cos²39°+sin²39°)
= 1-1 /*cos²A+sin²A=1*/
=0
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