Answer:
sec(4x) + C
Explanation:
original problem: ∫sec(4x)tan(x)dx
use integration by substitution (u-sub) by setting u = 4x
if u = 4x, then du/dx = 4 and du = 4dx (dx = du/4)
after substitution the integral is ∫sec(u)tan(u)(du/4)
move the 1/4 out of the integral by using the integral Constant rule to form 1/4∫sec(u)tan(u)du
the anti-derivative of sec(u)tan(u) is sec(u), memorize your trigonometric derivatives!!!!
after integration, we get sec(u)/4 + C , now plug u back into the equation
sec(4x) + C is the general solution
Answer:
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Answer:
D. desire to surprise his friend and his friend’s failure to recognize him
Explanation:
Answer D
Correct. In these sentences, the author presents a humorous reversal that emerges from the ironic incongruity between the traveler’s plan to “overpower” his old friend with an excess of pleasure and the anticlimactic outcome of the surprise visit. As it turns out, the friend experiences no immediate pleasure from the visit because he fails to recognize the traveler and can only be made to remember him after the traveler gives a “gradual (in this context, methodical) explanation” of who he is.
