(6×100)+(3×100)+(9×1)+(2×0.1)+(5×0. 01) standard form

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

The probability that a student graduating from suburban state university has student loans to pay off after graduation is .60. if two students are randomly selected from this university, what is the probability that neither of them has student loans to pay off after graduation?

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota