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AlgebraQuestion and Answers: Page 310

Question Number 60533 Answers: 1 Comments: 2

If A, B, C are angle of a triangle. Show that cos (1/2)C + cos (1/2)(A − B) = 2 sin (1/2)A sin (1/2)B

$$\mathrm{If}\:\:\mathrm{A},\:\mathrm{B},\:\mathrm{C}\:\:\mathrm{are}\:\mathrm{angle}\:\mathrm{of}\:\mathrm{a}\:\mathrm{triangle}.\:\mathrm{Show}\:\mathrm{that} \\ $$$$\:\:\:\:\:\:\mathrm{cos}\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{C}\:+\:\mathrm{cos}\:\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{A}\:−\:\mathrm{B}\right)\:\:=\:\:\mathrm{2}\:\mathrm{sin}\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{A}\:\mathrm{sin}\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{B} \\ $$

Question Number 60501 Answers: 1 Comments: 1

let A = ((( 1 1)),((1 1)) ) 1)calculate A^n 2) determine e^A and e^(−A) .

$${let}\:{A}\:=\begin{pmatrix}{\:\mathrm{1}\:\:\:\:\:\:\:\:\:\:\mathrm{1}}\\{\mathrm{1}\:\:\:\:\:\:\:\:\:\:\:\:\mathrm{1}}\end{pmatrix} \\ $$$$\left.\mathrm{1}\right){calculate}\:{A}^{{n}} \\ $$$$\left.\mathrm{2}\right)\:{determine}\:{e}^{{A}} \:\:\:{and}\:{e}^{−{A}} \:. \\ $$$$ \\ $$

Question Number 60500 Answers: 0 Comments: 2

let A = (((1 1)),((−2 3)) ) 1) find A^(−1) 2) calculate A^n 3) determine e^A and e^(−2A) .

$${let}\:{A}\:=\begin{pmatrix}{\mathrm{1}\:\:\:\:\:\:\:\mathrm{1}}\\{−\mathrm{2}\:\:\:\mathrm{3}}\end{pmatrix} \\ $$$$\left.\mathrm{1}\right)\:{find}\:{A}^{−\mathrm{1}} \\ $$$$\left.\mathrm{2}\right)\:{calculate}\:{A}^{{n}} \\ $$$$\left.\mathrm{3}\right)\:{determine}\:{e}^{{A}} \:\:\:{and}\:{e}^{−\mathrm{2}{A}} \:. \\ $$

Question Number 60475 Answers: 1 Comments: 0

Question Number 60453 Answers: 0 Comments: 0

Question Number 60445 Answers: 2 Comments: 1

Question Number 60416 Answers: 0 Comments: 0

Sum the series: ^n C_0 ^n C_1 + ^n C_1 ^n C_2 + ^n C_2 ^n C_3 + ... + ^n C_r ^n C_(r + 1)

$$\mathrm{Sum}\:\mathrm{the}\:\mathrm{series}:\:\:\:\overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{0}} \overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{1}} \:+\:\overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{1}} \overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{2}} \:+\:\overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{2}} \overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{3}} \:+\:...\:+\:\overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{r}} \overset{\mathrm{n}} {\:}\mathrm{C}_{\mathrm{r}\:+\:\mathrm{1}} \\ $$

Question Number 60406 Answers: 1 Comments: 0

n ∈ Z^+ , Find the coefficient of x^(−1) in the expansion of (1 + x)^n (1 + (1/x))^n

$$\mathrm{n}\:\in\:\mathbb{Z}^{+} ,\:\:\:\mathrm{Find}\:\mathrm{the}\:\mathrm{coefficient}\:\mathrm{of}\:\:\mathrm{x}^{−\mathrm{1}} \:\:\mathrm{in}\:\mathrm{the}\:\mathrm{expansion}\:\mathrm{of}\:\:\:\left(\mathrm{1}\:+\:\mathrm{x}\right)^{\mathrm{n}} \left(\mathrm{1}\:+\:\frac{\mathrm{1}}{\mathrm{x}}\right)^{\mathrm{n}} \\ $$

Question Number 60330 Answers: 0 Comments: 1

Question Number 60255 Answers: 0 Comments: 0

b=(((kT)/P))^(1/3) . distance molekular prove.

$$\boldsymbol{\mathrm{b}}=\sqrt[{\mathrm{3}}]{\frac{\boldsymbol{\mathrm{kT}}}{\boldsymbol{\mathrm{P}}}}.\:\boldsymbol{\mathrm{distance}}\:\:\boldsymbol{\mathrm{molekular}} \\ $$$$\boldsymbol{\mathrm{prove}}. \\ $$

Question Number 60175 Answers: 0 Comments: 2

solving u^v =w with u, v, w ∈C finding all possible solutions I tested this with several values and found no mistake. please review and comment. I hope this will help at least some of you.

$$\mathrm{solving}\:{u}^{{v}} ={w}\:\mathrm{with}\:{u},\:{v},\:{w}\:\in\mathbb{C} \\ $$$$\mathrm{finding}\:\mathrm{all}\:\mathrm{possible}\:\mathrm{solutions} \\ $$$$\mathrm{I}\:\mathrm{tested}\:\mathrm{this}\:\mathrm{with}\:\mathrm{several}\:\mathrm{values}\:\mathrm{and}\:\mathrm{found} \\ $$$$\mathrm{no}\:\mathrm{mistake}.\:\mathrm{please}\:\mathrm{review}\:\mathrm{and}\:\mathrm{comment}. \\ $$$$\mathrm{I}\:\mathrm{hope}\:\mathrm{this}\:\mathrm{will}\:\mathrm{help}\:\mathrm{at}\:\mathrm{least}\:\mathrm{some}\:\mathrm{of}\:\mathrm{you}. \\ $$

Question Number 60156 Answers: 3 Comments: 2

Prove by principle of mathematical induction sin(x) + sin(2x) + sin(3x) + ... + sin(nx) = ((cos((1/2)x) − cos(n + (1/2))x)/(2 sin((1/2)x)))

$$\mathrm{Prove}\:\mathrm{by}\:\mathrm{principle}\:\mathrm{of}\:\mathrm{mathematical}\:\mathrm{induction} \\ $$$$\:\:\:\:\:\:\:\:\mathrm{sin}\left(\mathrm{x}\right)\:+\:\mathrm{sin}\left(\mathrm{2x}\right)\:+\:\mathrm{sin}\left(\mathrm{3x}\right)\:+\:...\:+\:\mathrm{sin}\left(\mathrm{nx}\right)\:\:=\:\:\frac{\mathrm{cos}\left(\frac{\mathrm{1}}{\mathrm{2}}\mathrm{x}\right)\:−\:\mathrm{cos}\left(\mathrm{n}\:+\:\frac{\mathrm{1}}{\mathrm{2}}\right)\mathrm{x}}{\mathrm{2}\:\mathrm{sin}\left(\frac{\mathrm{1}}{\mathrm{2}}\mathrm{x}\right)} \\ $$

Question Number 60056 Answers: 1 Comments: 1

Question Number 60052 Answers: 0 Comments: 0

Question Number 60039 Answers: 2 Comments: 3

find all solutions for z∈C z^i =(1/2)−(1/2)i z^(1−i) =1+i

$$\mathrm{find}\:\mathrm{all}\:\mathrm{solutions}\:\mathrm{for}\:{z}\in\mathbb{C} \\ $$$${z}^{\mathrm{i}} =\frac{\mathrm{1}}{\mathrm{2}}−\frac{\mathrm{1}}{\mathrm{2}}\mathrm{i} \\ $$$${z}^{\mathrm{1}−\mathrm{i}} =\mathrm{1}+\mathrm{i} \\ $$

Question Number 59977 Answers: 1 Comments: 0

4×(5+5)

$$\mathrm{4}×\left(\mathrm{5}+\mathrm{5}\right) \\ $$

Question Number 59929 Answers: 0 Comments: 0

Use long division to solve 7485/5

$$\mathrm{Use}\:\mathrm{long}\:\mathrm{division}\:\mathrm{to}\:\mathrm{solve}\:\mathrm{7485}/\mathrm{5} \\ $$

Question Number 59833 Answers: 1 Comments: 0

Question Number 59678 Answers: 0 Comments: 0

Determine a,b,c in terms of α,β,γ. (a/b)−c=γ (b/c)−a=α (c/a)−b=β

$$\mathcal{D}{etermine}\:{a},{b},{c}\:{in}\:{terms}\:{of}\:\alpha,\beta,\gamma. \\ $$$$\:\:\:\:\frac{{a}}{{b}}−{c}=\gamma \\ $$$$\:\:\:\:\frac{{b}}{{c}}−{a}=\alpha \\ $$$$\:\:\:\:\frac{{c}}{{a}}−{b}=\beta \\ $$

Question Number 59615 Answers: 1 Comments: 0

6+((1/5)×7)

$$\mathrm{6}+\left(\frac{\mathrm{1}}{\mathrm{5}}×\mathrm{7}\right) \\ $$

Question Number 59614 Answers: 1 Comments: 0

1(1/7)+1(1/(14))

$$\mathrm{1}\frac{\mathrm{1}}{\mathrm{7}}+\mathrm{1}\frac{\mathrm{1}}{\mathrm{14}} \\ $$

Question Number 59581 Answers: 2 Comments: 0

Determine a , b , c in terms of α , β , γ. ab+c=γ bc+a=α ca+b=β

$$\mathcal{D}{etermine}\:{a}\:,\:{b}\:,\:{c}\:{in}\:{terms}\:{of}\:\alpha\:,\:\beta\:,\:\gamma. \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:{ab}+{c}=\gamma\: \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:{bc}+{a}=\alpha \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:{ca}+{b}=\beta \\ $$

Question Number 59552 Answers: 1 Comments: 0

(1/4)+((1/4)+(1/8))

$$\frac{\mathrm{1}}{\mathrm{4}}+\left(\frac{\mathrm{1}}{\mathrm{4}}+\frac{\mathrm{1}}{\mathrm{8}}\right) \\ $$

Question Number 59551 Answers: 1 Comments: 0

1.8×1.6

$$\mathrm{1}.\mathrm{8}×\mathrm{1}.\mathrm{6} \\ $$

Question Number 59550 Answers: 1 Comments: 0

9+(5×4+5^3 )

$$\mathrm{9}+\left(\mathrm{5}×\mathrm{4}+\mathrm{5}^{\mathrm{3}} \right) \\ $$

Question Number 59549 Answers: 2 Comments: 0

(1/5)×i i=7

$$\frac{\mathrm{1}}{\mathrm{5}}×\mathrm{i}\:\:\mathrm{i}=\mathrm{7} \\ $$

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