These graphs show up on Exam 3, usually as a 'find the period and asymptotes' question. Understanding asymptotes also helps in Section 7.5 when you're solving equations involving tangent β you need to know where the function exists and where it doesn't.
While sine and cosine make smooth, gentle waves, the other four trig functions have a wilder personality β they shoot off toward infinity at certain points. These "blow-up" points are called vertical asymptotes, and they're invisible walls the graph can never cross. Tangent and secant blow up wherever cosine is zero; cotangent and cosecant blow up wherever sine is zero.
Half the period of sine and cosine for the same B value
Same period formula as sine and cosine
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While sine and cosine make smooth, gentle waves, the other four trig functions have a wilder personality β they shoot off toward infinity at certain points. These "blow-up" points are called vertical asymptotes, and they're invisible walls the graph can never cross. Tangent and secant blow up wherever cosine is zero; cotangent and cosecant blow up wherever sine is zero.
The biggest thing to remember is the period difference. Tangent and cotangent are "impatient" β they repeat every instead of the usual . That means their pattern is twice as fast as sine and cosine. Secant and cosecant keep the same period as the sine/cosine waves they're built from.
Tangent rises from to between each pair of asymptotes β it always goes uphill. Cotangent does the opposite β it always goes downhill. Secant and cosecant form U-shaped branches that open up and down, hugging the peaks and valleys of cosine and sine respectively.
When graphing a transformed version like , the same A-B-C-D ideas from sine and cosine apply β just swap in the correct period formula. The most important step is finding where the asymptotes land, because they determine where each branch starts and ends. If there's a phase shift, the asymptotes shift too.
Half the period of sine and cosine for the same B value
Same period formula as sine and cosine
Where cos(x) = 0
Where sin(x) = 0
Phase shift = C/B, vertical stretch = |A|, vertical shift = D