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mathslover Group TitleBest ResponseYou've already chosen the best response.1
Prove : \(\sin (90  \theta) = \cos \theta\)
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
Actually I am confused that how can I : prove that sin in 2nd quadrant is +ve ? That is my basic confusion ...
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
can u use sin (AB) formula?
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
No idea. Actually that was just in start and the formula arises later, so I think that there must be an easier method?
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
draw a right triangle
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
:( not so good but OK ? :)
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
dw:1350046739720:dw nothing is there without naming , OK now I think.
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
dw:1350046691525:dw now find sin 90theta and cos theta using basic defination
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
OK wait please !
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
In case of sin 90  theta , will perpendicular be : adjacent (base) and base will be opposite?
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
know the basic defination of sin and cos ? dw:1350046897401:dw apply it here, in terms of a and b,c
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
OH IT IS soh cah toa and not soa cah toa , sorry :(
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
sin = opposite / hypotenuse cos = adjacent / hypotenuse
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
sin (90theta) = b/c cos (theta) = b/c and hence sin(90theta) = cos(theta) , got it now? lol jk. Well is this right @hartnn
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
yep, hence proved.
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
next identity please.
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
prove that sin in 2nd quadrant is +ve ? That is my basic confusion ...
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
here, put theta = theta
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
and use cos(theta) = cos theta
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
how to prove that cos(theta)=theta ?
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
again with the use of right triangle @hartnn ?
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
how will u find theta in triangle ?
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
oh yes .. silly me . So, a cartesian plane ?
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
no, cartesian plane will not work also.
 one year ago

sara12345 Group TitleBest ResponseYou've already chosen the best response.1
ccw : +ve angle cw : ve angle
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
because lengths will be positive , so ratio will always come out to be positive, hence, maybe cartesian plane won't work
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
Some how agreed .
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
searched net now, http://www.mathsisfun.com/algebra/trigfourquadrants.html is that the correct one ?
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
yes, its correct....we could prove it using coordinates.... (cos t,sin t)= (x,y) so sin t is +ve in 2nd quadrant
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
doubts ended :) thanks a lo.
 one year ago

mathslover Group TitleBest ResponseYou've already chosen the best response.1
*ton/lot.
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
mathisfun is always a nice reference....
 one year ago

sara12345 Group TitleBest ResponseYou've already chosen the best response.1
more we knw more confuse we become
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.8
more we practice, more the confusion vanishes....
 one year ago

sara12345 Group TitleBest ResponseYou've already chosen the best response.1
more we practice, more ways we look at things n hence more confusions which ofcourse gives kick ;p
 one year ago
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