Question

докажите тождество ((1-cos^2t)/(1-sin^2))+tgt*ctgt=(1)/(cos^2t)

Answer 1

$frac{1-cos^{2}t}{1-sin^{2}t}=frac{sin^{2}t}{cos^{2}t}$

 

$frac{sin^{2}t}{cos^{2}t}+1(*cos^{2})=1/cos^{2}t</var>$

 

$frac{sin^{2}t+cos^{2}t}{cos^{2}t}=frac{1}{cos^{2}}$

 

$frac{1}{cos^{2}}=frac{1}{cos^{2}}$