complex no. (1 Viewer)

=)(= · Nov 16, 2022

How would you do e?

=)(= · Nov 16, 2022

also for dis

shouldnt it just be angle aob instead of tan <aob

Drongoski · Nov 16, 2022

Q8(e)

The 2 values are related to the roots of:

$4x^2+2x-1 =0, $ viz $ \frac {-1 \pm \sqrt 5}{4}\\ \\ $So: $ sin\frac {\pi}{10} = \frac {-1+\sqrt 5}{4} $ and $ sin \frac {3\pi}{10} = - \frac{-1-\sqrt 5 }{4} = \frac {1+\sqrt 5}{4}$

Note:

$1) (4x^2+bx+c)^2 =16x^4 + b^2x^2 + c^2 +2(4bx^3 + 4cx^2 +bcx) \\ \\ = 16x^4 + 8bx^3 +(b^2+8c)x^2 + 2bcx + c^2 \implies b=2 $ and $ c=-1\\ \\ 2) sin\frac {3\pi}{10} = -sin\frac {13\pi}{10}$

=)(= · Nov 16, 2022

for sin3pi/10 why is there a negative infront

Drongoski · Nov 16, 2022

See Note-2 above.

=)(= · Nov 16, 2022

ahhh i see thanks

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