Question
Evaluate the following integrals:
$\int\sec^4\text{x}\tan\text{x}\text{ dx}$

Answer

Let $\text{I}=\int\sec^4\text{x}\tan\text{x}\text{ dx}\ ....(1)$
Let $\tan\text{x}=\text{t}$ then,
$\Rightarrow\text{d}(\tan\text{x})=\text{dt}$
$\Rightarrow\sec^2\text{x}\text{ dx}=\text{dt}$
$\Rightarrow\text{dx}=\frac{\text{dt}}{\sec^2\text{x}}$
Putting $\tan\text{x}=\text{t}$ and $\text{dx}=\frac{\text{dt}}{\sec^2\text{x}}$ in equation (1), we get,
$\text{I}=\int\sec^4\text{x}\tan\text{x}\frac{\text{dt}}{\sec^2\text{x}}$
$=\int\sec^2\text{x}\text{ t dt}$
$=\int\big(1+\tan^2\text{x}\big)\text{t dt}$
$=\int\big(1+\text{t}^2\big)\text{t dt}$
$=\int\big(\text{t}+\text{t}^3\big)\text{dt}$
$=\frac{\text{t}^2}{2}+\frac{\text{t}^4}{4}+\text{C}$
$=\frac{\tan^2\text{x}}{2}+\frac{\tan^4\text{x}}{4}+\text{C}$
$\text{I}=\frac{1}{2}\tan^2\text{x}+\frac{1}{4}\tan^4\text{x}+\text{C}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A factory uses three different resources for the manufacture of two different products, 20 units of the resources A, 12 units of B and 16 units of C being available. 1 unit of the first product requires 2, 2 and 4 units of the respective resources and 1 unit of the second product requires 4, 2 and 0 units of respective resources. It is known that the first product gives a profit of 2 monetary units per unit and the second 3. Formulate the linear programming problem. How many units of each product should be manufactured for maximizing the profit? Solve it graphically.
Find the inverse of the following matrices:$\begin{bmatrix} 1 & 0 & 0 \\ 0 & \cos\alpha & \sin\alpha \\ 0 & \sin\alpha & -\cos\alpha \end{bmatrix}$
There are three coins. One is two-headed coin (having head on both faces), another is biased coin that comes up heads 75% of the times and third is also a biased coin that comes up tail 40% of the times. One of the three coins is chosen at random and tossed, and it shows heads. What is the probability that it was the two-headed coin?
An urn contains 4 red and 3 blue balls. Find the probability distribution of the number of blue balls in a random draw of 3 balls with replacement.
The probability that a certain kind of component will survive a given shock test is $\frac{3}{4}.$ Find the probability that among 5 components tested.
  1. exactly 2 will survive.
  2. at most 3 will survive.
Classify the following functions as injection, surjection or bijection:f : R → R, defined by f(x) = 3 - 4x
Prove The Following : $\int \frac{1}{\sqrt{x^2-a^2}} \cdot d x=\log \left(x+\sqrt{x^2-a^2}\right)+c$
A firm manufactures two products A and B on which profit earned per unit ₹3/- and ₹4/- respectively. Each product is processed on two machines M1 and M2. The product A requires one minute of processing time on M1 and two minute of processing time on M2, B requires one minute of processing time on M1 and one minute of processing time on M2. Machine M1 is available for use for 450 minutes while M2 is available for 600 minutes during any working day. Find the number of units of product A and B to be manufactured to get the maximum profit.
Find the shortest distance between the lines $\bar{r}=(4 \hat{i}-\hat{j})+\lambda(\hat{i}+2 \hat{j}-3 \hat{k})$ and

$\bar{r}=(\hat{i}-\hat{j}+2 \hat{k})+\mu(\hat{i}+4 \hat{j}-5 \hat{k})$

With usual notations show that $\left(c^2-a^2+b^2\right) \tan A=\left(a^2-b^2+c^2\right) \tan B=\left(b^2-c^2+a^2\right)$tan C.