Mathematics

Eleven Standard

Test your understanding of this lesson Trigonometric ratios of angle 18 degrees:-

1)
Value of \(\cos18^{0}\) is
  • \(\frac{\sqrt{5}-1}{4}\)
  • \(\frac{\sqrt{5}+1}{4}\)
  • -\(\frac{\sqrt{5}+1}{4}\)
  • \(\frac{1-\sqrt{5}}{4}\)
2)
Value of \(\cos18^{0}\) is
  • \(\frac{1}{4}\sqrt{10+2\sqrt{5}}\)
  • \(\frac{1}{4}\sqrt{10-2\sqrt{5}}\)
  • \(\frac{\sqrt{5-1}}{4}\)
  • \(\frac{\sqrt{5+1}}{4}\)
3)
Value of \(\tan18^{0}\) is
  • \(\sqrt{\frac{3+\sqrt{5}}{5-\sqrt{5}}}\)
  • \(\sqrt{\frac{3+\sqrt{5}}{5+\sqrt{5}}}\)
  • \(\sqrt{\frac{3-\sqrt{5}}{5+\sqrt{5}}}\)
  • \(\sqrt{\frac{3-\sqrt{5}}{5-\sqrt{5}}}\)
4)
Value of \(sin72^{0}\) is
  • \(\frac{1}{4}\sqrt{10-2\sqrt{5}}\)
  • \(\frac{1}{4}\sqrt{10+2\sqrt{5}}\)
  • \(\frac{\sqrt{5}-1}{4}\)
  • \(\frac{\sqrt{5}+1}{4}\)
5)
Value of \(\tan72^{0}\) is
  • \(\sqrt{\frac{3-\sqrt{5}}{5+\sqrt{5}}}\)
  • \(\sqrt{\frac{5+\sqrt{5}}{3-\sqrt{5}}}\)
  • \(\sqrt{\frac{3-\sqrt{5}}{5-\sqrt{5}}}\)
  • \(\sqrt{\frac{5-\sqrt{5}}{3-\sqrt{5}}}\)

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