Not sure but you can figure it out.
6.0 because if it is 0-4, you round down and 5-9, round up
For an investment compounded continuously, the rule of 69 gives a better approximation than the rule of 72 (for normal compound interests).
Step-by-step explanation:
tanB + cotB = (sinB)/(cosB) + (cosB)/(sinB)
= (sin2B + cos2B)/[(cosB)(sinB)]
= 1/[(cosB)(sinB)]
= (1/cosB)(1/sinB)
= (secB)(cscB)