Evaluate the following limits in Exercises 1 to 22.
0
Explanation
The question asks to evaluate the limit of x sec x as x approaches 0. Using the definition sec x = 1/cos x, we can rewrite the expression. From the context, we know that lim(x→0) cos x = 1. Using the property of limits shown in the context (where limits can be separated for sums and products), we can evaluate this limit by separating it into lim(x→0) x divided by lim(x→0) cos x. Since lim(x→0) x = 0 and lim(x→0) cos x = 1, the result is 0/1 = 0.
Solution Steps
Step 1: Rewrite sec x as 1/cos x, so lim(x→0) x sec x = lim(x→0) x/cos x
Step 2: Apply the limit property: lim(x→0) x/cos x = lim(x→0) x ÷ lim(x→0) cos x
Step 3: Since lim(x→0) x = 0 and lim(x→0) cos x = 1 (from context)
Step 4: Therefore, lim(x→0) x sec x = 0/1 = 0