∫sec2x4tan2x+9dx 13tan−12tanx3+C 16tan−12tanx3+C 16tan−
![∫sec2x4tan2x+9dx 13tan−12tanx3+C 16tan−12tanx3+C 16tan−](/img/relate-questions.png)
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∫sec2(x)4tan2(x)+9dx
A.
13tan−1(2tan(x)3)+C
B.
16tan−1(2tan(x)3)+C
C.
16tan−1(tan(x)6)+C
D.
16tan−1(2tan(x)5)+C
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Here, if we put tan(x) = t the numerator sec2(x) dx will become dt. As sec2(x) is the derivative of tan(x). And we’ll be left with a quadratic equation in the denominator which we can solve.
Let’s substitute tan(x) = t
So, sec2(x) dx = dt
And the given integral would be like
∫14t2+9dtOr 14∫1t2+94dtOr 14∫1t2+3(32)2dt
We can see that this is of the form ∫1x2+a2dx
After using the corresponding formula and substituting back the value of “ t “ which is tan(x) we get the final answer equal to16tan−1(2tan(x)3)+C