sol`n

Solutions to Diff Cal Test #2 Practice Problems:
1. Use the product rule to differentiate.
𝑓𝑓(π‘₯π‘₯) = cot π‘₯π‘₯ (π‘₯π‘₯ + 4)2⁄3
2
𝑓𝑓 β€² (π‘₯π‘₯) = (βˆ’ csc 2 π‘₯π‘₯)(π‘₯π‘₯ + 4)2⁄3 + (cot π‘₯π‘₯) οΏ½ (π‘₯π‘₯ + 4)βˆ’1⁄3 οΏ½
3
2. Use the quotient rule to differentiate.
𝑓𝑓(π‘₯π‘₯) =
2π‘₯π‘₯ 3 βˆ’ 4π‘₯π‘₯ 2 + 5π‘₯π‘₯ βˆ’ 9
5 sec π‘₯π‘₯
𝑓𝑓 β€² (π‘₯π‘₯) =
(5 sec π‘₯π‘₯)(6π‘₯π‘₯ 2 βˆ’ 8π‘₯π‘₯ + 5) βˆ’ (2π‘₯π‘₯ 3 βˆ’ 4π‘₯π‘₯ 2 + 5π‘₯π‘₯ βˆ’ 9)(5 sec π‘₯π‘₯ tan π‘₯π‘₯)
(5 sec π‘₯π‘₯)2
3. Find the derivative of 𝑓𝑓 with respect to π‘₯π‘₯.
𝑓𝑓(π‘₯π‘₯) = 5 sin2 οΏ½οΏ½3 csc(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯)οΏ½ = 5οΏ½sinοΏ½(3 csc(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯))1⁄2 οΏ½οΏ½
2
1
𝑓𝑓 β€² (π‘₯π‘₯) = 10 sin(3 csc(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯))1⁄2 βˆ™ cos(3 csc(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯))1⁄2 βˆ™ (3 csc(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯))βˆ’1⁄2
2
βˆ™ (βˆ’3 csc(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯) cot(7π‘₯π‘₯ 2 βˆ’ 2π‘₯π‘₯)) βˆ™ (14π‘₯π‘₯ βˆ’ 2)
4. Find the derivative of 𝑓𝑓 with respect to π‘₯π‘₯.
𝑓𝑓(π‘₯π‘₯) = βˆ’3π‘₯π‘₯ cot(5π‘₯π‘₯ 2 + 4π‘₯π‘₯) = βˆ’(3π‘₯π‘₯ ) cot(5π‘₯π‘₯ 2 + 4π‘₯π‘₯)
𝑓𝑓 β€² (π‘₯π‘₯) = (βˆ’3π‘₯π‘₯ ln 3)(cot(5π‘₯π‘₯ 2 + 4π‘₯π‘₯)) + (βˆ’3π‘₯π‘₯ )(βˆ’ csc 2 (5π‘₯π‘₯ 2 + 4π‘₯π‘₯))(10π‘₯π‘₯ + 4)
5. Find the derivative of 𝑓𝑓 with respect to π‘₯π‘₯.
𝑓𝑓(π‘₯π‘₯) = log 2 cos(5π‘₯π‘₯)
𝑓𝑓 β€² (π‘₯π‘₯) =
(βˆ’ sin 5π‘₯π‘₯)(5)
(ln 2)(cos 5π‘₯π‘₯)
6. Find the derivative of 𝑓𝑓 with respect to π‘₯π‘₯.
𝑓𝑓(π‘₯π‘₯) = arcsin(π‘₯π‘₯ 2 βˆ’ 7π‘₯π‘₯)
𝑓𝑓 β€² (π‘₯π‘₯) =
2π‘₯π‘₯ βˆ’ 7
οΏ½1 βˆ’ (π‘₯π‘₯ 2 βˆ’ 7π‘₯π‘₯)2
7. Find the derivative of 𝑓𝑓 with respect to π‘₯π‘₯.
𝑓𝑓(π‘₯π‘₯) = 𝑒𝑒 arctan(2π‘₯π‘₯+5)
𝑓𝑓 β€² (π‘₯π‘₯) = 𝑒𝑒 arctan(2π‘₯π‘₯+5) βˆ™
2
1 + (2π‘₯π‘₯ + 5)2
8. Find the derivative of 𝑓𝑓 with respect to π‘₯π‘₯.
𝑓𝑓(π‘₯π‘₯) = arccsc π‘₯π‘₯ ln(tan(2π‘₯π‘₯))
𝑓𝑓
β€² (π‘₯π‘₯)
=οΏ½
βˆ’1
|π‘₯π‘₯|√π‘₯π‘₯ 2 βˆ’ 1
οΏ½ (ln(tan 2π‘₯π‘₯)) + (arccsc π‘₯π‘₯) οΏ½
(sec 2 2π‘₯π‘₯)(2)
οΏ½
tan 2π‘₯π‘₯