(i) Given that

when
this reduces to






(ii) Differentiate
implicitly with respect to
. By the chain and product rules,

(iii) Differentiating both sides of the given equation leads to

where we use the result from (ii) for the derivative of
.
Solve for
:





From part (i), we have
and
, and substituting these leads to



as required.
A. Is 41 degrees, B. Is 44 degrees
i really thinks its 6.9*10 to the power of 2
True because tan(20)=2.1 and cot(20)=is o.44
Plan A:
15+(0.25x)
15+(0.25×80)
15+(20)
35
Plan B:
20+(0.05x)
20+(0.05×300)
20+(15)
35
I am sure there are other numbers that you can use but I just choose the number 35! Good luck!