Question 1
Use the chain rule: when $y=(ax+b)^n$, $\frac{\mathrm{d}y}{\mathrm{d}x}=an{(ax+b)}^{n-1}$ to differentiate the following:
a) $y={(2x+1)}^3$
b) $y={(3x+2)}^4$
c) $y={(8x+15)}^{10}$
d) $y={(x+3)}^{7}$
e) $y={(3x+4)}^{2}$
f) $y={(4x-6)}^6$
g) $y={(-2x+3)}^5$
h) $y={(-5x-1)}^8$
i) $y={(6x+5)}^{-2}$
j) $y={(-2x-1)}^{-3}$
k) $y={(8x+1)}^{\frac32}$
l) $y={(5x+3)}^{\frac12}$
Question 2
First write in the form $y=(ax+b)^n$ and then differentiate:
a) $y={(1+2x)}^{3}$
b) $y={(8-4x)}^{5}$
c) $y={(-3-3x)}^{-3}$
d) $y={(1+x)}^{-1}$
e) $y=\frac{1}{1+x}$
f) $y=\frac{1}{x-3}$
g) $y=\frac{1}{{(x+4)}^2}$
h) $y=\frac{1}{{(2x-3)}^3}$
i) $y=\frac{1}{{(5-2x)}^5}$
j) $y=\sqrt{(2x+1)}$
k) $y=\sqrt{{(6x+4)}^3}$
l) $y=\frac{1}{\sqrt[4]{{(16x-3)}^3}}$
Question 3
Use the chain rule and the fact that when $y=af(x)$, $\frac{\mathrm{d}y}{\mathrm{d}x}=af'(x)$ to differentiate the following:
a) $y=2{(2x+1)}^3$
b) $y=5{(3x+2)}^4$
c) $y=-2{(8x+3)}^6$
d) $y=-7{(x+3)}^5$
e) $y=-3{(-2x-4)}^6$
f) $y=5{(4-3x)}^2$
g) $y=-3{(6-x)}^{-1}$
h) $y=6{(6x-3)}^{\frac43}$
i) $y=2\sqrt[3]{(3+12x)}$
Question 4
Use the chain rule to differentiate the following:
a) $y={(x^2+1)}^3$
b) $y={(x^3+7)}^4$
c) $y={(2x^2+5)}^2$
d) $y={(3x^4-15)}^7$
e) $y={(15-3x^3)}^3$
f) $y=5{(3x^2-22)}^8$
g) $y=-5{(2x^3+15)}^5$
h) $y={(x^2+x)}^3$
i) $y={(4x^5+3x^2)}^6$
j) $y={(x^2+x+1)}^4$
k) $y={(4x^3+x^2-24)}^3$
l) $y={(3-2x^2-5x^3+6x^6)}^7$
Question 5
Differentiate these:
a) $y=\frac{2}{{(2x+5)}^3}$
b) $y=-\frac{10}{{(5-x)}^2}$
c) $y=\frac{-4}{{(2x^2+3x-1)}^6}$
d) $y=6\sqrt[5]{(3x^4-18x+2)}$
e) $y=-\frac{2}{\sqrt{{(2-x^3)}^7}}$
f) $y=-\frac{22}{\sqrt[3]{{(5-x^2+4x^5)}^{10}}}$
Question 6
Find the answer to the following worded questions:
a) Find the value of $\frac{\mathrm{d}y}{\mathrm{d}x}$ when $y={(2x+4)}^5$ when $x=3$
b) Find the value of $\frac{\mathrm{d}y}{\mathrm{d}x}$ when $y=2{(3x-4)}^3$ when $x=2$
c) Find the gradient on the graph $y={(5-x)}^3$ when $x=1$
d) Find the gradient on the graph $y={(x^2-1)}^3$ at the point $(2,27)$
Answers
Question 1
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(2x+1)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=12{(3x+2)}^3$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=80{(8x+15)}^9$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=7{(x+3)}^6$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(3x+4)}$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=24{(4x-6)}^5$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-10{(-2x+3)}^4$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=-40{(-5x-1)}^7$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=-12{(6x+5)}^{-3}$
j) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(-2x-1)}^{-4}$
k) $\frac{\mathrm{d}y}{\mathrm{d}x}=12{(8x+1)}^{\frac12}$
l) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac52{(5x+3)}^{-\frac12}$
Question 2
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(1+2x)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=-20{(8-4x)}^4$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=9{(-3-3x)}^{-4}$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=-{(1+x)}^{-2}$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{1}{{(1+x)}^2}$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{1}{{(x-3)}^2}$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{2}{{(x+4)}^3}$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{6}{{(2x-3)}^4}$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{10}{{(5-2x)}^6}$
j) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{1}{\sqrt{2x+1}}$
k) $\frac{\mathrm{d}y}{\mathrm{d}x}=9\sqrt{6x+4}$
l) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{12}{\sqrt[4]{16x-3}^7}$
Question 3
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=12{(2x+1)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=60{(3x+2)}^3$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=-96{(8x+3)}^5$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=-35{(x+3)}^4$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=36{(-2x-4)}^5$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=-30(4-3x)$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-3{(6-x)}^{-2}$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=48{(6x-3)}^{\frac13}$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{8}{\sqrt[3]{{(3+12x)}^2}}$
Question 4
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=6x{(x^2+1)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=12x^2{(x^3+7)}^3$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=8x{(2x^2+5)}$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=84x^3{(3x^4-15)}^6$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=-27x^2{(15-3x^3)}^2$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=240x{(3x^2-22)}^7$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-150x^2{(2x^3+15)}^4$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=3{(2x+1)}{(x^2+x)}^2$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(20x^4+6x)}{(4x^5+3x^2)}^5$
j) $\frac{\mathrm{d}y}{\mathrm{d}x}=4{(2x+1)}{(x^2+x)}^3$
k) $\frac{\mathrm{d}y}{\mathrm{d}x}=3{(12x^2+2x)}{(4x^3+x^2-24)}^2$
l) $\frac{\mathrm{d}y}{\mathrm{d}x}=7{(-4x-15x^2+36x^5)}{(3-2x^2-5x^3+6x^6)}^6$
Question 5
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{12}{{(2x+5)}^4}$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{20}{{(5-x)}^3}$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{96x+72}{{(2x^2+3x-1)}^7}$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{72x^3-108}{5\sqrt[5]{{(3x^4-18x+2)}^4}}$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{21x^2}{\sqrt{{(2-x^3)}^9}}$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{\frac{4400}{3}x^4-\frac{440}{3}x}{\sqrt[3]{{(5-x^2+4x^5)}^{13}}}$
Question 6
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=300\,000$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=144$
c) Gradient is $-48$
d) Gradient is $108$
Question 1
Use the chain rule: when $y=(ax+b)^n$, $\frac{\mathrm{d}y}{\mathrm{d}x}=an{(ax+b)}^{n-1}$ to differentiate the following:
a) $y={(2x+1)}^3$
b) $y={(3x+2)}^4$
c) $y={(8x+15)}^{10}$
d) $y={(x+3)}^{7}$
e) $y={(3x+4)}^{2}$
f) $y={(4x-6)}^6$
g) $y={(-2x+3)}^5$
h) $y={(-5x-1)}^8$
i) $y={(6x+5)}^{-2}$
j) $y={(-2x-1)}^{-3}$
k) $y={(8x+1)}^{\frac32}$
l) $y={(5x+3)}^{\frac12}$
Question 2
First write in the form $y=(ax+b)^n$ and then differentiate:
a) $y={(1+2x)}^{3}$
b) $y={(8-4x)}^{5}$
c) $y={(-3-3x)}^{-3}$
d) $y={(1+x)}^{-1}$
e) $y=\frac{1}{1+x}$
f) $y=\frac{1}{x-3}$
g) $y=\frac{1}{{(x+4)}^2}$
h) $y=\frac{1}{{(2x-3)}^3}$
i) $y=\frac{1}{{(5-2x)}^5}$
j) $y=\sqrt{(2x+1)}$
k) $y=\sqrt{{(6x+4)}^3}$
l) $y=\frac{1}{\sqrt[4]{{(16x-3)}^3}}$
Question 3
Use the chain rule and the fact that when $y=af(x)$, $\frac{\mathrm{d}y}{\mathrm{d}x}=af'(x)$ to differentiate the following:
a) $y=2{(2x+1)}^3$
b) $y=5{(3x+2)}^4$
c) $y=-2{(8x+3)}^6$
d) $y=-7{(x+3)}^5$
e) $y=-3{(-2x-4)}^6$
f) $y=5{(4-3x)}^2$
g) $y=-3{(6-x)}^{-1}$
h) $y=6{(6x-3)}^{\frac43}$
i) $y=2\sqrt[3]{(3+12x)}$
Question 4
Use the chain rule to differentiate the following:
a) $y={(x^2+1)}^3$
b) $y={(x^3+7)}^4$
c) $y={(2x^2+5)}^2$
d) $y={(3x^4-15)}^7$
e) $y={(15-3x^3)}^3$
f) $y=5{(3x^2-22)}^8$
g) $y=-5{(2x^3+15)}^5$
h) $y={(x^2+x)}^3$
i) $y={(4x^5+3x^2)}^6$
j) $y={(x^2+x+1)}^4$
k) $y={(4x^3+x^2-24)}^3$
l) $y={(3-2x^2-5x^3+6x^6)}^7$
Question 5
Differentiate these:
a) $y=\frac{2}{{(2x+5)}^3}$
b) $y=-\frac{10}{{(5-x)}^2}$
c) $y=\frac{-4}{{(2x^2+3x-1)}^6}$
d) $y=6\sqrt[5]{(3x^4-18x+2)}$
e) $y=-\frac{2}{\sqrt{{(2-x^3)}^7}}$
f) $y=-\frac{22}{\sqrt[3]{{(5-x^2+4x^5)}^{10}}}$
Question 6
Find the answer to the following worded questions:
a) Find the value of $\frac{\mathrm{d}y}{\mathrm{d}x}$ when $y={(2x+4)}^5$ when $x=3$
b) Find the value of $\frac{\mathrm{d}y}{\mathrm{d}x}$ when $y=2{(3x-4)}^3$ when $x=2$
c) Find the gradient on the graph $y={(5-x)}^3$ when $x=1$
d) Find the gradient on the graph $y={(x^2-1)}^3$ at the point $(2,27)$
Answers
Question 1
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(2x+1)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=12{(3x+2)}^3$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=80{(8x+15)}^9$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=7{(x+3)}^6$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(3x+4)}$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=24{(4x-6)}^5$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-10{(-2x+3)}^4$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=-40{(-5x-1)}^7$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=-12{(6x+5)}^{-3}$
j) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(-2x-1)}^{-4}$
k) $\frac{\mathrm{d}y}{\mathrm{d}x}=12{(8x+1)}^{\frac12}$
l) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac52{(5x+3)}^{-\frac12}$
Question 2
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(1+2x)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=-20{(8-4x)}^4$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=9{(-3-3x)}^{-4}$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=-{(1+x)}^{-2}$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{1}{{(1+x)}^2}$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{1}{{(x-3)}^2}$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{2}{{(x+4)}^3}$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{6}{{(2x-3)}^4}$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{10}{{(5-2x)}^6}$
j) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{1}{\sqrt{2x+1}}$
k) $\frac{\mathrm{d}y}{\mathrm{d}x}=9\sqrt{6x+4}$
l) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{12}{\sqrt[4]{16x-3}^7}$
Question 3
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=12{(2x+1)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=60{(3x+2)}^3$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=-96{(8x+3)}^5$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=-35{(x+3)}^4$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=36{(-2x-4)}^5$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=-30(4-3x)$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-3{(6-x)}^{-2}$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=48{(6x-3)}^{\frac13}$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{8}{\sqrt[3]{{(3+12x)}^2}}$
Question 4
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=6x{(x^2+1)}^2$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=12x^2{(x^3+7)}^3$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=8x{(2x^2+5)}$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=84x^3{(3x^4-15)}^6$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=-27x^2{(15-3x^3)}^2$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=240x{(3x^2-22)}^7$
g) $\frac{\mathrm{d}y}{\mathrm{d}x}=-150x^2{(2x^3+15)}^4$
h) $\frac{\mathrm{d}y}{\mathrm{d}x}=3{(2x+1)}{(x^2+x)}^2$
i) $\frac{\mathrm{d}y}{\mathrm{d}x}=6{(20x^4+6x)}{(4x^5+3x^2)}^5$
j) $\frac{\mathrm{d}y}{\mathrm{d}x}=4{(2x+1)}{(x^2+x)}^3$
k) $\frac{\mathrm{d}y}{\mathrm{d}x}=3{(12x^2+2x)}{(4x^3+x^2-24)}^2$
l) $\frac{\mathrm{d}y}{\mathrm{d}x}=7{(-4x-15x^2+36x^5)}{(3-2x^2-5x^3+6x^6)}^6$
Question 5
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{12}{{(2x+5)}^4}$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{20}{{(5-x)}^3}$
c) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{96x+72}{{(2x^2+3x-1)}^7}$
d) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{72x^3-108}{5\sqrt[5]{{(3x^4-18x+2)}^4}}$
e) $\frac{\mathrm{d}y}{\mathrm{d}x}=-\frac{21x^2}{\sqrt{{(2-x^3)}^9}}$
f) $\frac{\mathrm{d}y}{\mathrm{d}x}=\frac{\frac{4400}{3}x^4-\frac{440}{3}x}{\sqrt[3]{{(5-x^2+4x^5)}^{13}}}$
Question 6
a) $\frac{\mathrm{d}y}{\mathrm{d}x}=300\,000$
b) $\frac{\mathrm{d}y}{\mathrm{d}x}=144$
c) Gradient is $-48$
d) Gradient is $108$