1. Use the identities:
to verify that / is indeed the identity in question.
Surely you know what to do next?
don't even know how to begin, does it involve factor/sum formulae?
angle ABC and angle ADC is 90 deg respectively. because AC is diameter.
angle BAD is 180deg-θ°. because of cyclic quadrilateral.....
how do i relate them and find AD?
sin x cos x = -(3/10)
then ....can i do this :
sin x = - (3/10) , cos x = - (3/10)
??? or i can only do this when it's equal to zero?
what i tried to do:
thus, i roughly know it would be something like (x^2)+(y^2).....
and then......i'm stuck ="=
how am i going to find the radius ...
and the question never mention about radius/diameter...
10 sin x cos x +3 =0
(5)(2)sin x cos x =-3
5 sin 2x =-3
sin 2x = -(3/5)
basic angle of 2x = 36.87 deg
90deg < x < 180 deg .......=> second quadrant
2x= (180deg - 36.87deg)
2x= 143.13 deg
x= 71.565 deg
there's no this answer among the choices.....
where did i went wrong ?? @"@
based on my sixth sense, i feel that the part i higlighted in bold is incorrect/weird/etc(don't know how to describe)..........
i mean the unknown, a.