I am ABSOLUTLY stuck on this idenity problem! Anyone please help!
Prove algebraically that the equation is an identity:
(5cosC-2sinC)^2+(2cosC+5sinC)^2=29
Please help! Thank you so much!
I am ABSOLUTLY stuck on this idenity problem! Anyone please help!
Prove algebraically that the equation is an identity:
(5cosC-2sinC)^2+(2cosC+5sinC)^2=29
Please help! Thank you so much!
Hi wiseguy,
$\displaystyle (5 \cos C - 2 \sin C)^2+(2 \cos C+5 \sin C)^2=29$
$\displaystyle 25\cos^2 C-20 \cos C \sin C+4 \sin^2 C + (4\cos^2 C+20 \cos C \sin C+ 25 \sin^2 C)=29$
$\displaystyle 29 \cos^2 C+29 \sin^2 C=29$
$\displaystyle 29(\cos^2 C+\sin^2 C)=29$
$\displaystyle 29(1)=29$
$\displaystyle 29=29$