Identify Substitution: Let's start by identifying a substitution that can simplify the integral. We notice that the derivative of tan(3t) is sec2(3t) multiplied by the constant 3. This suggests that a substitution involving tan(3t) might be useful. Let's set u=tan(3t), which means dtdu=3sec2(3t).
Express in terms of u: Now we need to express the integral in terms of u. We have du=3sec2(3t)dt, so dt=3sec2(3t)du. We also need to express the sec2(3t) term in the numerator in terms of u. Since sec2(3t)=1+tan2(3t), we can write sec2(3t) as 1+u2.
Substitute u and dt: Substituting u and dt into the integral, we get:∫7+2tan(3t)6sec2(3t)dt=∫7+2u6(1+u2)⋅(3(1+u2)du)Simplifying this, we get:∫7+2u6⋅(3du)=∫7+2u2du
Integrate rational function: The integral ∫7+2u2du is a simple rational function, and we can integrate it directly. The antiderivative of a+bu1 with respect to u is (b1)ln∣a+bu∣, so the antiderivative of 7+2u2 with respect to u is (21)ln∣7+2u∣.
Substitute back to t: Now we substitute back the original variable t into our antiderivative. Since u=tan(3t), we have:(1/2)ln∣7+2u∣=(1/2)ln∣7+2tan(3t)∣+C, where C is the constant of integration.
Final Antiderivative: We have found the antiderivative, so the integral of 7+2tan(3t)6sec2(3t) with respect to t is: \frac{\(1\)}{\(2\)}\ln|\(7+2\tan(3t)| + C
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