Trig Fns - Identities
Interactive practice questions
Find the value of $\sin\left(\frac{5\pi}{36}\right)\cos\left(\frac{\pi}{36}\right)+\sin\left(\frac{\pi}{36}\right)\cos\left(\frac{5\pi}{36}\right)$sin(5π36)cos(π36)+sin(π36)cos(5π36) in exact form.
Easy
2min
Find the exact value of $\cos\frac{21\pi}{10}\cos\frac{\pi}{10}+\sin\frac{21\pi}{10}\sin\frac{\pi}{10}$cos21π10cosπ10+sin21π10sinπ10.
Easy
1min
Find the exact value of $\frac{\tan\frac{2\pi}{9}-\tan\frac{\pi}{18}}{1+\tan\frac{2\pi}{9}\tan\frac{\pi}{18}}$tan2π9−tanπ181+tan2π9tanπ18.
Easy
2min
Suppose $\cos A=\frac{3}{5}$cosA=35 and $\sin B=\frac{15}{17}$sinB=1517, where $0
Easy
12min
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