Math Problem Statement

Solve a set of math problems including evaluating trigonometric expressions, finding polar coordinates, solving exponential equations, and performing set operations.

Solution

Let me help solve the questions from the image.

Q3: Find the degree and radian measure of the exterior angle of a regular pentagon.

A regular polygon's exterior angle is given by: Exterior Angle=360n\text{Exterior Angle} = \frac{360^\circ}{n} For a pentagon (n=5n = 5): Exterior Angle=3605=72\text{Exterior Angle} = \frac{360^\circ}{5} = 72^\circ To convert it to radians: 72×π180=2π5radians72^\circ \times \frac{\pi}{180^\circ} = \frac{2\pi}{5} \, \text{radians} Answer: 7272^\circ or 2π5\frac{2\pi}{5} radians.


Q4: Evaluate 4cot45sec260+sin304 \cot 45^\circ - \sec^2 60^\circ + \sin 30^\circ.

We first compute the trigonometric values:

  • cot45=1\cot 45^\circ = 1
  • sec60=2sec260=4\sec 60^\circ = 2 \Rightarrow \sec^2 60^\circ = 4
  • sin30=12\sin 30^\circ = \frac{1}{2}

Now, substitute these values: 4cot45sec260+sin30=4(1)4+12=44+12=124 \cot 45^\circ - \sec^2 60^\circ + \sin 30^\circ = 4(1) - 4 + \frac{1}{2} = 4 - 4 + \frac{1}{2} = \frac{1}{2} Answer: 12\frac{1}{2}.


Q5: Find the polar coordinates of the point whose Cartesian coordinates are (5,5)(5, 5).

To convert from Cartesian (x,y)(x, y) to polar (r,θ)(r, \theta), we use:

  • r=x2+y2r = \sqrt{x^2 + y^2}
  • θ=tan1(yx)\theta = \tan^{-1}\left(\frac{y}{x}\right)

Given (x,y)=(5,5)(x, y) = (5, 5): r=52+52=50=52r = \sqrt{5^2 + 5^2} = \sqrt{50} = 5\sqrt{2} θ=tan1(55)=tan1(1)=45=π4radians\theta = \tan^{-1}\left(\frac{5}{5}\right) = \tan^{-1}(1) = 45^\circ = \frac{\pi}{4} \, \text{radians} Answer: (52,π4)\left( 5\sqrt{2}, \frac{\pi}{4} \right).


Q6: Solve 52x+7=1255^{2x + 7} = 125.

We rewrite 125125 as 535^3, so the equation becomes: 52x+7=535^{2x + 7} = 5^3 Since the bases are the same, equate the exponents: 2x+7=32x + 7 = 3 Solve for xx: 2x=37=42x = 3 - 7 = -4 x=2x = -2 Answer: x=2x = -2.


Q7: If A={1,2,3}A = \{1, 2, 3\} and B={a,b}B = \{a, b\}, find A×BA \times B.

The Cartesian product A×BA \times B consists of all ordered pairs (x,y)(x, y) where xAx \in A and yBy \in B: A×B={(1,a),(1,b),(2,a),(2,b),(3,a),(3,b)}A \times B = \{(1, a), (1, b), (2, a), (2, b), (3, a), (3, b)\} Answer: {(1,a),(1,b),(2,a),(2,b),(3,a),(3,b)}\{(1, a), (1, b), (2, a), (2, b), (3, a), (3, b)\}.


Q8: If f(x)=x2+2f(x) = x^2 + 2 and g(x)=2x25g(x) = 2x^2 - 5, find (f+g)(x)(f + g)(x).

The function (f+g)(x)(f + g)(x) is defined as: (f+g)(x)=f(x)+g(x)(f + g)(x) = f(x) + g(x) Substitute the given functions: (f+g)(x)=(x2+2)+(2x25)=x2+2x2+25=3x23(f + g)(x) = (x^2 + 2) + (2x^2 - 5) = x^2 + 2x^2 + 2 - 5 = 3x^2 - 3 Answer: 3x233x^2 - 3.


Would you like any further details or clarifications on any of these problems?

Here are 5 related questions:

  1. How do you calculate the exterior angle of an octagon?
  2. What is the general formula for the cotangent of an angle?
  3. How do you convert polar coordinates to Cartesian coordinates?
  4. What happens if 52x+7=6255^{2x+7} = 625?
  5. Can you describe the properties of Cartesian products?

Tip: When solving trigonometric expressions, always ensure you're working in the correct unit (degrees or radians).

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Polar Coordinates
Exponential Equations
Set Theory
Algebra

Formulas

Exterior Angle of a Regular Polygon: (360/n)
Trigonometric Identities: cot(θ), sec(θ), sin(θ)
Polar Coordinates: r = √(x^2 + y^2), θ = tan⁻¹(y/x)
Exponential Equation: a^(x) = b
Set Cartesian Product: A × B

Theorems

Trigonometric Functions
Exponential Equations
Cartesian Product of Sets

Suitable Grade Level

Grades 10-12