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Question Number 18719 by Tinkutara last updated on 28/Jul/17

$$\mathrm{If}{\cos }^2{x}_1+{\cos }^2{x}_2+{\cos }^2{x}_3+{\cos }^2{x}_4$$$$+{\cos }^2{x}_5=5,\mathrm{then}\sin x_1+2\sin x_2+$$$$3\sin x_3+4\sin x_4+5\sin x_5\mathrm{is}\mathrm{less}\mathrm{than}$$$$\mathrm{or}\mathrm{equal}\mathrm{to}$$

Commented by mrW1 last updated on 28/Jul/17

$$0$$$$\cos {\mathrm{x}}_{\mathrm{i}}=\pm 1\Rightarrow \sin {\mathrm{x}}_{\mathrm{i}}=0$$$$\Rightarrow \mathrm{\Sigma }\left(\mathrm{i}\sin {\mathrm{x}}_{\mathrm{i}}\right)=0$$

Commented by Tinkutara last updated on 29/Jul/17

$$\mathrm{Thanks}\mathrm{Sir}!$$

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