Maths / Introduction to Trigonometry / Trigonometric ratios for 30 degrees

QUESTION
 

The value of the expression 2;cos^2;A -1  when A= 30 is ____________.

 

OPTIONS
A. 

4sqrt3

B. 

frac{1}{2}

C. 

2sqrt3

D. 

0

Right Option : B

EXPLANATION
Explain TypeExplanation Content
Text

2;cos^2;A -1 

2;cos^2;30^0 -1 

=2;(frac{sqrt3}{2})^2 -1 = 2 ;X;frac{3}{4}-1 = frac{3}{2}-1=frac{1}{2}

 

 

 

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