证明 1-tanh^2(x)=sech^2(x)

解答

证明

1 - tanh^{2} (x) = sech^{2} (x)

真

求解步骤

1 - tanh^{2} (x) = sech^{2} (x)

使用双曲函数恒等式:

1 - tanh^{2} (x) = sech^{2} (x)

\Rightarrow 真

p ro v e cos (π - x) = - cos (x)

p ro v e \frac{1 + sin ( θ )}{1 - sin ( θ )} - \frac{1 - sin ( θ )}{1 + sin ( θ )} = 4 tan (θ) sec (θ)

p ro v e cos (7 x) + cos (3 x) = 2 cos (5 x) cos (2 x)

p ro v e cot (- α) cos (- α) + sin (- α) = - csc (α)

p ro v e sin (θ) cos (θ) tan (θ) = 1 - cos^{2} (θ)