IIT JEE , AIEEE Forum - Mathematics , Trignometry

ayshwarya

wats d value of Tan70 -2Cot 40 =Tanx 2 maro ish d exjam

2 2 2 2 2 2

Sin 12 +Sin 21 +Sin 39 +Sin 48 -Sin 9 - Sin 18

If 3 vectors a,b,c such dat a 0 & axb = 2(axc) , IaI =IcI=1 , IbI =4 & d angle btw b ,c is cos^-1 [1/4] , den b-2c =lambda (a)

[a b c ] =3 den [2axb +2bxc +cxa] . [2axb - bxc - 2cxa]x[axb -2bxc +2cxa] =?

let a,b,c b non 0 vectors such dat (axb)xc =1/3 IbI IcI a .if teta is d acute angl btw d vectors b & c , den Sin[teta] =?

If d area of a triangl is 5s.u ; den d area of d triangl when d origin is shifted 2

(2,-1) is ?

ayshwarya

pls yaaron ive est 2maro

ayshwarya

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ayshwarya

Bolo Bharat Mata ki jaaaaaaaaaaaaaaaaaaaaaai

jaaaaaaaaaaaaaai hiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiind

sboosy

tan70-2cot40
tan70+2cot(180-40)
tan70+2cot140
tan70+2(cot^2(70)-1)/2cot70
tan70+cot70-tan70
=cot70

sboosy

what does the second question mean? is it sin square theta?

ayshwarya

s its square teta

ayshwarya

s its sin square teta

sboosy

grouping sin square 12 with sin square 18 and sin square 21 with sin square 9
using the formula
sin(A+B)sin(A-B)=sin square (A)-sin square (B)
we get
1/2[sin12-sin6]
sin square 39 = (1- cos 78)/2
sin square 48 = (1- cos 96)/2
also cos 78= cos (90-12)=sin12
cos96=cos(90+6)= -sin 6
using both adding we get answer =1

sboosy

Could u retype the last question u have posted
there seem to be something missing in that

aditi_g

i think sin theta shud be sqrt 8/3
coz cos theta is 1/3...and angle between a and c will be 90

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