Join 60,000+ competitive exam aspirants
What is the value of sin┬▓(30┬░) + cos┬▓(30┬░)?
0
0.5
1
2
1
Recognize the fundamental Pythagorean identity of trigonometry: for any angle heta, sin2(heta)+cos2(heta) is always equal to 1, regardless of the angle value.
An expression containing the square of the sine and cosine of the angle 30 degrees.
sin2(╬╕)+cos2(╬╕)=1
Recognize the fundamental Pythagorean identity of trigonometry: for any angle ╬╕, sin2(╬╕)+cos2(╬╕) is always equal to 1, regardless of the angle value.
Many students waste time calculating values like sin(30┬░)=1/2 and cos(30┬░)=3тАЛ/2 instead of applying the direct identity.
Identify the Identity
Recognize that the expression follows the standard trigonometric identity sin2(╬╕)+cos2(╬╕)=1 for any value of ╬╕.
sin2(╬╕)+cos2(╬╕)=1
Apply Identity
Since the angle in the expression sin2(30┬░)+cos2(30┬░) is ╬╕=30┬░ for both terms, the sum must be 1.
sin2(30┬░)+cos2(30┬░)=1
Verification
Calculating manually: sin(30┬░)=1/2 and cos(30┬░)=3тАЛ/2. Squaring them gives (1/2)2+(3тАЛ/2)2=1/4+3/4=4/4=1.
(21тАЛ)2+(23тАЛтАЛ)2=41тАЛ+43тАЛ=1
C is correct because the trigonometric identity sin2(╬╕)+cos2(╬╕)=1 holds true for any angle, including 30┬░.
This identity is the foundation for solving problems involving circle equations (x2+y2=r2) and is frequently used to simplify complex integration in Engineering Mathematics.