Which of the following angles can be used to evaluate cot(-210°)

-

Step-by-step explanation:

We know that cot (-x)  = -cot x

                therefore  cot(-210) = -cot(210)

                                     and we know that cot (180+x) = cot(x)

                              [since 210 lies in  third quadrant therefore its positive ]        

                     therefore  cot(180+30 ) = cot 30

 so here in the question

     cot(-210) = -cot(210)  = - cot (30)

                                         = -

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!