Math, asked by kashwini526, 4 months ago

please give the correct answer it's humble request ❤❤❤❤❤​

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Answered by Mihir1001
3

\underline{\bold{\red{Question} }} :

 \sf \: Prove  \: that  :  \quad  1 + i ^{10} + i ^{20} + i ^{30} = 0

\underline{| \bold{\green{Answer} }} :

 \begin{aligned} \mathbb{LHS} \\  \\  =  \:  & \sf1 +  {i}^{10}  +  {i}^{20} +  {i}^{30} \\  \\  = \: &  \sf1  +  {( {i}^{2} )}^{5}  +  {( {i}^{2} )}^{10}  +  {( {i}^{2} )}^{15} \\  \\  =  \: &1 +  {( - 1)}^{5}   +  {( - 1)}^{10}  +  {( - 1)}^{15} \\  \\& \quad [ \because {i}^{2}   =  \sqrt{ - 1} \times  \sqrt{ - 1}  =  - 1  ]  \\  \\   =  \: &1 +  {( - 1)}^{5} + { \big[ {( - 1)}^{2}  \big]}^{5}   +  { \big[ {( - 1)}^{3}  \big]}^{5}  \\  \\  =   \: &1  +  {( - 1)}^{5} +  {(1)}^{5} {( - 1)}^{5}    \\  \\  =  \: &1 + ( - 1) +(1) + ( - 1) \\  \\  =  \: & \cancel1 -  \cancel1 +  \cancel1 -  \cancel1 \\  \\  =  \:&0 \\  \\  =  \: & \mathbb{RHS}  \end{aligned}

Hence , Proved !

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.... Thank You !!!

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Answered by ayush2005301
0

Step-by-step explanation:

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