Question and Answers Forum

All Questions      Topic List

Algebra Questions

Previous in All Question      Next in All Question      

Previous in Algebra      Next in Algebra      

Question Number 108628 by I want to learn more last updated on 18/Aug/20

Prove that the inequality  ∣cos x∣  ≥   1  −  sin^2 x    hold true for all  x ∈ R

$$\mathrm{Prove}\:\mathrm{that}\:\mathrm{the}\:\mathrm{inequality}\:\:\mid\mathrm{cos}\:\mathrm{x}\mid\:\:\geqslant\:\:\:\mathrm{1}\:\:−\:\:\mathrm{sin}^{\mathrm{2}} \mathrm{x}\:\:\:\:\mathrm{hold}\:\mathrm{true}\:\mathrm{for}\:\mathrm{all}\:\:\mathrm{x}\:\in\:\mathbb{R} \\ $$

Commented by mr W last updated on 18/Aug/20

∣cos x∣≤1  ⇒∣cos x∣≥cos^2  x=1−sin^2  x

$$\mid\mathrm{cos}\:{x}\mid\leqslant\mathrm{1} \\ $$$$\Rightarrow\mid\mathrm{cos}\:{x}\mid\geqslant\mathrm{cos}^{\mathrm{2}} \:{x}=\mathrm{1}−\mathrm{sin}^{\mathrm{2}} \:{x} \\ $$

Commented by I want to learn more last updated on 18/Aug/20

Thanks sir, i appreciate.

$$\mathrm{Thanks}\:\mathrm{sir},\:\mathrm{i}\:\mathrm{appreciate}. \\ $$

Commented by I want to learn more last updated on 18/Aug/20

please sir help with   Q 108626

$$\mathrm{please}\:\mathrm{sir}\:\mathrm{help}\:\mathrm{with}\:\:\:\mathrm{Q}\:\mathrm{108626} \\ $$

Commented by Aziztisffola last updated on 18/Aug/20

look at the answer to get an idea.

$$\mathrm{look}\:\mathrm{at}\:\mathrm{the}\:\mathrm{answer}\:\mathrm{to}\:\mathrm{get}\:\mathrm{an}\:\mathrm{idea}. \\ $$

Terms of Service

Privacy Policy

Contact: info@tinkutara.com