Let r and `r^(')` denote the angles iniside an equilateral prism, as usual, in degrees. Consider that during some time interval from `t=0` to`t=t,r^(')` varies with time as `r^(')=10+t^(2)`. During this time, r will vary as (assume that r and `r^(')` are in degree)

Options

A. `50-t^(2)`
B. `50+t^(2)`
C. `60-t^(2)`
D. `60+t^(2)`

Answer

a.

Explanation

In a prism `:r+r^(')=ArArr r=A-r^(')`
`:. r=60^(@)-(10+t^(2))=50-t^(2)`