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Verify that cos 2x = 2 cos2 x -1

\(\begin{array}{l}\cos 2x =\cos ^{2}x -\sin ^{2}x\end{array} \)——(i) We have learnt that \(\begin{array}{l}\cos ^{2}x + \sin ^{2}x=1\end{array} \) So \(\begin{array}{l}\sin ^{2}x=1... View Article

How do you find lim cosx/x as x->0?

\(\begin{array}{l}\lim_{x\rightarrow 0}\frac{cos x}{x}=\infty\end{array} \) Explanation \(\begin{array}{l}\lim_{x\rightarrow 0}\frac{cos x}{x}\end{array} \) As \(\begin{array}{l}x\rightarrow 0\end{array} \) \(\begin{array}{l}cosx\rightarrow cos 0 = 1\end{array} \) and... View Article

Explain tan 2x formula

\(\begin{array}{l}Tan 2x =\frac{2tan x}{1-tan^{2}x} \end{array} \) Derivation Tan 2x =\frac{2tan x}{1-tan^{2}x} \end{array} \) As per the addition formula. \(\begin{array}{l}tan(a+b) =\frac{... View Article