CBSE > Class 10 > Mathematics | CBSE Board | Homework Help

Let n = 4q + 1 (an odd integer)
{tex}\therefore \quad n ^ { 2 } - 1 = ( 4 q + 1 ) ^ { 2 } - 1{/tex}
{tex}= 16 q ^ { 2 } + 1 + 8 q - 1 \quad \text { Using Identity } ( a + b ) ^ { 2 } = a ^ { 2 } + 2 a b + b ^ { 2 }{/tex}
{tex}= 16{q^2} + 8q{/tex}
{tex}= 8 \left( 2 q ^ { 2 } + q \right){/tex}
= 8m, which is divisible by 8.

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Ten years ago father was twelve times as old as his son & ten years hence , he will be twice as old as his son .find their present ages

Posted by Neelu Chouhan 7 years, 9 months ago

CBSE > Class 10 > Mathematics

1 answers

Ankit Gupta 7 years, 9 months ago

Let the present age of father be x and his son be y. Atq x-10=12y x+10 =2y By any method we can these equations

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According to new syllabus has any capter been deleted

Posted by Abhishek Ranjan 7 years, 9 months ago

CBSE > Class 10 > Mathematics

1 answers

Tanu Priya 7 years, 9 months ago

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How marks questions will come from ncert

Posted by Animesh Singh Singh 7 years, 9 months ago

CBSE > Class 10 > Mathematics

0 answers

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How much mark is need for securing A grade

Posted by Aiswarya Anil 7 years, 9 months ago

CBSE > Class 10 > Mathematics

4 answers

Sahil Kumar 7 years, 9 months ago

Above 70 out of 80

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Yash Kumar 7 years, 9 months ago

I don't know

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Tanu Priya 7 years, 9 months ago

Out of 80

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Tanu Priya 7 years, 9 months ago

60 - 70

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what is median class?? plz tell

Posted by Amanpreet Singh 7 years, 9 months ago

CBSE > Class 10 > Mathematics

1 answers

Tanu Priya 7 years, 9 months ago

Middle most observation in the data

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The first term is 1 and d is 2 then Find the 9th term .

Posted by Mithun Kumar 7 years, 9 months ago

CBSE > Class 10 > Mathematics

5 answers

Raj Sharma 7 years, 9 months ago

a=1 d=2 a9= a+8d a9=1+8X2 a9=1+16 a9=17

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Shamanth Koggi 7 years, 9 months ago

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Shashank Tomar 7 years, 9 months ago

A+8d 1+8×2 1+16 17 Hence ninth term is 17

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Tanu Priya 7 years, 9 months ago

Sorry ismein galti se type ho gaya really sorry

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Tanu Priya 7 years, 9 months ago

Middle most observation in the data

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The decimal expansion of 141÷120 will terminate after how many places

Posted by Anku Singh 7 years, 9 months ago

CBSE > Class 10 > Mathematics

0 answers

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If we have given H. C.F. than how to find L.C.M?

Posted by Mohd Shezal 7 years, 9 months ago

CBSE > Class 10 > Mathematics

2 answers

Mohd Shezal 7 years, 9 months ago

Thanks

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Shashank Tomar 7 years, 9 months ago

The simple formula to find one either lcm or hcf is hcf×lcm= a×b product of two no.s

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If the sum of m terms of and A.P. is the same as the sum of its n terms, Then the sum its(m+n) terms is?

Posted by Mohd Shezal 6 years, 6 months ago

CBSE > Class 10 > Mathematics

1 answers

Sia ? 6 years, 6 months ago

Let a be the first term and d be the common difference of the given A.P. Then,
S_m = S_n
{tex}\Rightarrow \quad \frac { m } { 2 } \{ 2 a + ( m - 1 ) d \} = \frac { n } { 2 } \{ 2 a + ( n - 1 ) d \}{/tex}
{tex} \Rightarrow{/tex}2a (m - n) + {m (m - 1) - n (n - 1)} d = 0
{tex} \Rightarrow{/tex} 2a (m - n) + {m² - m - n² + n}d = 0
{tex} \Rightarrow{/tex}2a (m - n) + {(m² - n²) - (m - n)} d = 0
{tex} \Rightarrow{/tex}2a (m - n) + {(m - n) (m +n) - (m - n)} d = 0
{tex} \Rightarrow{/tex}(m - n) {2a + (m + n - 1)d} = 0
{tex} \Rightarrow{/tex} 2a + (m + n - 1)d = 0{tex} [ \because m - n \neq 0 ]{/tex} ...(i)
Now, {tex} S _ { m + n } = \frac { m + n } { 2 } \{ 2 a + ( m + n - 1 ) d \} = \frac { m + n } { 2 } \times {/tex}0 = 0 [Using (i)]