ok......practice for CBSE math.....easy stuff

THIS IS SERIOUSLY NOT FOR IITJEE practice.....THEY ARE 2222222 EASY............ ONLY FOR CBSE sure shot QUESTIONS...

Please other guys dont scold me for these easy questions..
1. Find the principal value of tan-1(tan7∩/6)+cot-1cot7∩/6.....

2.Evaluate...o∫∩/2(x+sinx)dx/(1+cosx)...

3.Two tailors A and B earn Rs.150 and Rs. 200 per day respectively. A can stich 6 shirts and 4 pants per day whike B can stich 10 shirts and 4 pants per day. How many days shall each work if it desired to produce atleast 60 shirts and 32 pants at a minimum labour cost?? GRAPHICALLY..........

Solve these yaar u cud be sure of 11 marks in d next board paper..

61 Answers

1
Akand ·

ya richa rite..........cud u give d solutions also???? coz i hav a doubt in 7.........and try 6 and 9 sldo hehe ;)

1
KR ·

=o∫∩/2(x+sinx)dx/(1+cosx)...

=o∫∩/2(x)dx/(1+cosx)+o∫∩/2(sinx)dx/(1+cosx)...
=o∫∩/2(x)dx/(2cos2x/2)-1∫0dt/(1+t)...{t=sinx}
=1/2o∫∩/2(x)sec2(x/2)dx/+o∫1dt/(1+t)...
=1/2([2xtan(x/2)]0π/2-20∫π/2tan(x/2)dx/2+[log|1+t|]01
its easy now integral tanx=log|sinx|

11
Mani Pal Singh ·

wat is use of writing ques[7]
akhnd yaar dimag aur nahin chal raha cbse mein to beda garg ho gaya
please post some more easy but conceptual ques and do tell that integration

1
prateek punj ·

@KR...yaar is my answer wrong....

1
prateek punj ·

please reply yaar....akand please look into the matter....

1
KR ·

[12]

1
KR ·

itz coming π/2 for me too

1
Akand ·

yup prateek perfect............sorry dint see

11
Mani Pal Singh ·

nahin maine kya different kiya tha MR AKAND in#28

which shorter method u were talking about???

1
Akand ·

MR MS..........if it was just sec2x in d numerator then ur method is the best.....but it is xsec2x in ur method....... uske baad kya karega???? and look at prateek's method???? usse chota hoga kya???? BOL..

11
Mani Pal Singh ·

TERI BAINS KI AANKH
maiine bhi to integeration by parts hi use karne ko hi kaha tha[16]

1
Akand ·

TERI BHAINS KAA WO.......main bola urs was correct BUT long....just look at d size of prateek's answer dude.....

1
Akand ·

next CBSE question........
4. If the sum of two unit vectors is a unit vector, Prove that the magnitude of their difference is √3.

5.If a and b(bar) are position vectors of points A and B respectively, then find the position vector of points of trisection of AB.

1
Akand ·

next.......6 . 7. 8. questions 7 8 are veryyyyyyy easyyyyyy

one more awesum wala....
9.

1
vector ·

cos(inv)1/6
dt prodct 6

11
Mani Pal Singh ·

@akand #43
YAAR TU TO CHA GAYA
MAYHS MEIN SIZE KO DEKTA HAI[3]

MATHEMATICIANS HAASENGE[3]

WAISE NICE JOKE[3]

1
prateek punj ·

tell me if i'm wrong....

1
Akand ·

haha....MS.........har question kaa hazaaron tarilke hote hai BUT we need the best one and d smartest and easiest one ok??? and NOW stop blabbering and do the other questions..

11
Mani Pal Singh ·

k

BUT i was
RIGHT[4]

1
Akand ·

only for practice for CBSE math integrations......................
easy ones...............NO need for solutions only practice ........for ur benefit..........

if u want to answer ........then answer 3,4,8,13,18,22,23,29.........they are good......PS...21 is already done in d forum and is a very good question

11
Mani Pal Singh ·

Q9
to prove sinθ/2=1/2|a^-b^|

|a-b|2=a2+b2-2a.b

=2-2cosθ

=2(1-cosθ)

=>4sin2θ/2=|a^-b^|2

=>2sinθ/2=|a-b|

=>sinθ/2=1/2|a^ -b^|

HENCE PROVED

1
vector ·

-c (vectr) is the resultant of a n b as they cant be cllinear n thus sm is solved

1
Akand ·

ya nice work guys...........try 6.......

1
Akand ·

but richa i was gettin cos-1(-1/2) for it........i may be wrong...

1
vector ·

6 is lagrange identity na i dunno hw to prve it

11
Mani Pal Singh ·

6)
i am not writing arrows on the top of vectors 4 convenience

(aXb)2

=|a|2|b|2sin2θ

=a2b2-a2b2cos2θ

=(a.a)(b.b)-(a.b)(a.b)

=RHS

1
Akand ·

excellent manipal..............thnx anyways.....this was eating my head.u r a genius dude...

1
ankit mahapatra ·

6.\frac{5}{6}(\frac{6x-2+2-2}{1+2x+3x^{2}})\frac{5}{6}\int (\frac{6x+2}{1+2x+3x^{2}})-\frac{20}{6}\int \frac{1}{1+2x+3x^{2}}

In first take denominator as t u get derivative in numerator.
in second make the denominator perfect square.

1
Akand ·

nice one ankit.....u cau just have written.......
d(den.)/dx=A(num.)+B......thts all.......hehe

1
Akand ·

k 10............
PROVE
(cos31°+sin31°)/(cos31°-sin31°)=tan76°..........

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