Question 816479
Can you help me prove the identity:
1+tan^2x=1/cos^2x
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{{{1+tan^2(x)=1/cos^2(x)}}}
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Start with the left side: (the more complex side)
{{{1+tan^2(x)}}}
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{{{1+(sin^2(x)/cos^2(x))}}}
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{{{(cos^2(x)+sin^2(x))/cos^2(x)=1/cos^2(x)}}}
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verified: 
left side=right side