Math Problem Statement

Question 6 Which of the following expressions is equal to (sin 60°)(cos 30°) + (cos 60°)(sin 30°)?

Solution

We need to simplify the expression:

(sin60)(cos30)+(cos60)(sin30)(\sin 60^\circ)(\cos 30^\circ) + (\cos 60^\circ)(\sin 30^\circ)

Step-by-step Solution:

  1. Substitute the trigonometric values for the specific angles:

    • sin60=32\sin 60^\circ = \frac{\sqrt{3}}{2}
    • cos30=32\cos 30^\circ = \frac{\sqrt{3}}{2}
    • cos60=12\cos 60^\circ = \frac{1}{2}
    • sin30=12\sin 30^\circ = \frac{1}{2}

    So, the expression becomes:

    (32)(32)+(12)(12)\left( \frac{\sqrt{3}}{2} \right) \left( \frac{\sqrt{3}}{2} \right) + \left( \frac{1}{2} \right) \left( \frac{1}{2} \right)

  2. Simplify each term:

    • 32×32=34\frac{\sqrt{3}}{2} \times \frac{\sqrt{3}}{2} = \frac{3}{4}
    • 12×12=14\frac{1}{2} \times \frac{1}{2} = \frac{1}{4}

    Now the expression becomes:

    34+14\frac{3}{4} + \frac{1}{4}

  3. Add the fractions:

    34+14=44=1\frac{3}{4} + \frac{1}{4} = \frac{4}{4} = 1

Final Answer:

(sin60)(cos30)+(cos60)(sin30)=1(\sin 60^\circ)(\cos 30^\circ) + (\cos 60^\circ)(\sin 30^\circ) = 1

This expression is equal to 1.

Would you like a deeper explanation of any of these steps?


Here are 5 related questions to practice:

  1. Simplify (sin45)(cos45)+(cos45)(sin45)(\sin 45^\circ)(\cos 45^\circ) + (\cos 45^\circ)(\sin 45^\circ).
  2. What is the value of sin(30+60)\sin(30^\circ + 60^\circ)?
  3. Prove the identity: sin(A+B)=sinAcosB+cosAsinB\sin(A + B) = \sin A \cos B + \cos A \sin B.
  4. Evaluate sin30+cos60\sin 30^\circ + \cos 60^\circ.
  5. Simplify the expression (sin90)(cos0)(\sin 90^\circ)(\cos 0^\circ).

Tip: Trigonometric identities like sin(A+B)\sin(A + B) can help simplify complex expressions!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angle identities
Trigonometric functions

Formulas

sin(A + B) = sin A cos B + cos A sin B

Theorems

Sum of angles identity for sine

Suitable Grade Level

Grades 9-11