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CBSE Class 12-science Answered

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Asked by sourabh7jain | 16 Jun, 2016, 05:32: PM
Expert Answer
open vertical bar table row cell negative 1 end cell cosC cosB row cosC cell negative 1 end cell cosA row cosB cosA cell negative 1 end cell end table close vertical bar equals space minus 1 left parenthesis 1 space minus space cos squared straight A right parenthesis minus cosC left parenthesis negative cosC minus cosAcosB right parenthesis space plus space cosB space left parenthesis cosAcosC minus cosB right parenthesis equals negative 1 space plus space cos squared straight A space plus space space cos squared straight C plus cosA space cosB space cosC plus cosA space cosB space cosC plus cos squared straight B equals space cos squared straight A space plus space cos squared straight B space plus space space cos squared straight C space plus space 2 cosA space cosB space cosC space minus space 1 equals space cos squared straight A space plus space cos squared straight B space plus space space cosC space left square bracket cosC space plus space 2 space cosA space cosB right square bracket space minus space 1 Now comma space straight A space plus space straight B space plus space straight C space equals space straight pi space rightwards double arrow space straight A space plus space straight B space equals straight pi space minus space straight C rightwards double arrow cos space left parenthesis straight A space plus space straight B right parenthesis space equals cos left parenthesis straight pi space minus space straight C right parenthesis rightwards double arrow cos space left parenthesis straight A space plus space straight B right parenthesis space equals negative space cos space straight C... left parenthesis straight i right parenthesis So comma space cos squared straight A space plus space cos squared straight B space plus space space cosC space left square bracket cosC space plus space 2 space cosA space cosB right square bracket space minus space 1 equals space cos squared straight A space plus space cos squared straight B space minus cos space left parenthesis straight A space plus space straight B right parenthesis left square bracket negative cos space left parenthesis straight A space plus space straight B right parenthesis space plus space 2 space cosA space cosB right square bracket space minus space 1.... left parenthesis from space left parenthesis straight i right parenthesis right parenthesis equals cos squared straight A space plus space cos squared straight B space minus cos space left parenthesis straight A space plus space straight B right parenthesis left square bracket negative cos space left parenthesis straight A space plus space straight B right parenthesis space plus space cos left parenthesis straight A plus straight B right parenthesis plus cos left parenthesis straight A minus straight B right parenthesis right square bracket space minus space 1 space space space space space space space space space space space space space space space space space space space space space..... space left parenthesis Since space 2 space cosAcosB space equals space cos left parenthesis straight A plus straight B right parenthesis plus cos left parenthesis straight A minus straight B right parenthesis right square bracket equals cos squared straight A space plus space cos squared straight B space minus cos space left parenthesis straight A space plus space straight B right parenthesis cos left parenthesis straight A minus straight B right parenthesis space minus space 1 equals cos squared straight A space plus space cos squared straight B space minus left square bracket cos squared straight A space minus sin squared straight B right square bracket space minus space 1 space space space space space space space space space space space space space space space space space space space space space..... space left parenthesis Since space cos space left parenthesis straight A plus straight B right parenthesis cos left parenthesis straight A minus straight B right parenthesis equals cos squared straight A space minus sin squared straight B right square bracket equals cos squared straight A space plus space cos squared straight B space minus cos squared straight A space plus sin squared straight B space minus space 1 equals 1 space minus 1 equals 0
Answered by Rebecca Fernandes | 17 Jun, 2016, 11:47: AM

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CBSE 12-science - Maths
open vertical bar table row cell left parenthesis straight b plus straight c right parenthesis hat 2 end cell ab ca row ab cell left parenthesis straight a plus straight c right parenthesis hat 2 end cell bc row ac bc cell left parenthesis straight a plus straight b right parenthesis hat 2 end cell end table close vertical bar equals 2 abc left parenthesis straight a plus straight b plus straight c right parenthesis hat 3
Asked by indupremachandran | 26 May, 2019, 01:08: PM
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CBSE 12-science - Maths
If A is a 2×2 matrix such that|A|= 5. Find |4A|
Asked by denpeter4 | 30 Apr, 2019, 01:30: PM
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CBSE 12-science - Maths
Using the properties of determinants,prove that  open vertical bar table row 1 cell straight a squared plus bc end cell cell straight a cubed end cell row 1 cell straight b plus ca end cell cell straight b cubed end cell row 1 cell straight i squared plus ab end cell cell straight C cubed end cell end table close vertical bar = -(a-b)(b-c)(c-a)(a3+b3+c3)   Pls note it is c instead of  i 
Asked by lekhakarthikeyan | 27 Dec, 2018, 02:23: AM
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CBSE 12-science - Maths
evaluate (solve each and every part) each determinant 67    19        21                          29      26       22                       102     18    36                     39    13        14               (b)      25      31       27        (c)               1        3    4             81    24        26                          63      54       46                         17        3     6   (d)  12   22   32 22    32   42 32     42  52
Asked by haroonrashidgkp | 10 Apr, 2018, 08:44: PM
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CBSE 12-science - Maths
(x-2)2                    (x-1)2                   x2 (X-1)2                       X2                   (x + 1)2                           =  -8 X2                      (x + 1)2                  (x + 2)2
Asked by haroonrashidgkp | 10 Apr, 2018, 08:35: PM
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CBSE 12-science - Maths
Express the system of linear equations in matrix form: a1x + b1y + c1z = d1, a2x + b2y + c2z = d2 and a3x + b3y + c3z = d3
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
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CBSE 12-science - Maths
Write the conditions for a solution of a system of linear equations AX = B.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
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CBSE 12-science - Maths
Write the given system of linear equations in matrix form. 2x – 3y = 1, x + 3z = 11 and x + 2y + z = 7.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
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CBSE 12-science - Maths
Find whether the system of linear equation has a unique solution or not. 5x – 10y = 4 and x – 2y = 8.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
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CBSE 12-science - Maths
Ravi purchases 1 pen, 4 pencils and 1 box in Rs. 34. From the same store Neeraj purchases 2 pens, 2 pencils in Rs. 26 and Neetu purchases 1 pen, 3 pencils and 2 boxes in Rs. 43. Express this problem into matrix form.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
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