What is 8 39/40 as a decimal

we have

we know that

In this problem we have a mixed number

A mixed number is a number expressed as the sum of a whole number and a fraction

so

Convert the fraction in a decimal number

Sum the whole number and the decimal number

therefore

the answer is

answer: cos [   arcsin (3/5) - arccos (1/2) ] =

step-by-step explanation: × = 3/5 = 0.6--> x = 36.87 and x = 180 - 36.87 = 143.13 deg

cos y = 1/2 --> y = +- 60 deg a. cos (x - y) = cos (143.13 - 60) = cos 83,13  

=

0.12

b. cos (36.87 - 60) = cos (-23.23) = 0.92