Step-5

Title: Trigonometry Identities ( Pythagorean, reciporcal)

Grade: 1300-a Lesson: S3-L3

Explanation: Hello Students, time to practice and review the steps for the problem.

Lesson Steps

Step Type Explanation Answer

1

Problem

Simplify \$(("sin"^2\theta) /("cos"\theta)) + (("cos"^2\theta) /("sin"\theta))\$.

2

Step

The given values expression is

\$(("sin"^2\theta) /("cos"\theta)) + (("cos"^2\theta) /("sin"\theta))\$

3

Hint

To simplify the given expression, let’s first express \$sin^2θ\$ and \$cos^2θ\$ in terms of sin θ and cos θ:

\$ sin^2 θ = 1 - cos^2 θ \$ (using the Pythagorean identity)

\$ cos2 θ = 1 - sin^2 θ \$ (using the Pythagorean identity)

4

Step

Now, substitute these values into the expression

\$(("sin"^2\theta) /("cos"\theta)) + (("cos"^2\theta) /("sin"\theta))\$

⇒ \$(1 - cos^2θ) /(cosθ) + (1 - sin^2θ) /(sinθ)\$

⇒ \$1/(cosθ) - (cos^2θ)/(cosθ) + 1/(sinθ) - (sin^2θ)/(sinθ)\$

⇒ \$1/(cosθ) - cosθ + 1/(sinθ) - sinθ\$

⇒ \$secθ - cosθ + cscθ - sinθ\$

5

Step

So, the simplified expression is \$secθ − cosθ + cscθ − sinθ\$.

6

Choice.A

Option A simplifies the expression by using trigonometric identities, substituting and combining terms for simplification

\$secθ - cosθ + cscθ - sinθ\$

7

Choice.B

This choice changes the order of terms, making it different from the original expression

\$cosθ + secθ + sinθ + cscθ\$

8

Choice.C

This choice switches the signs of all terms, which is incorrect

\$cosθ − secθ + sinθ − cscθ \$

9

Choice.D

This choice rearranges the terms, which is different from the original expression

\$secθ + cosθ − cscθ + sinθ\$

10

Answer

Option

A

11

Sumup

Can you briefly tell me what you’ve learned and understood in today’s lesson?


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