This question is from trigonometry topic – trigonometric ratios on complementary angles and it is already asked in previous year paper of 2008 in which we have to show that 2/3cosec²58° – 2/3cot58°tan42° – 5/3tan13°tan37°Tan45°tan53°tan77° = -1

RS Aggarwal, Class 10, chapter 12, question no 15