Question

cos27+sin27÷cos–sin27= cot 18 or 72
formula: a²–b²=(a+b)(a–b)​

Answer 1

Step-by-step explanation:

cos27+sin27/cos27-sin27

=(cos27+sin27)(cos27+sin27)/cos²27-sin²27

=cos²27+sin²27+2cos27sin27/ cos²27+sin²27+cos²27-sin²27-1

=1+sin2*27/cos2*27

=sec2*27+tan2*27

=sec3*18+tan3*18

=COT18