Trigonometry Examples

Find the Exact Value sec((11pi)/24)
sec(11π24)sec(11π24)
Step 1
Rewrite 11π24 as an angle where the values of the six trigonometric functions are known divided by 2.
sec(11π122)
Step 2
Apply the reciprocal identity to sec(11π122).
1cos(11π122)
Step 3
Apply the cosine half-angle identity cos(x2)=±1+cos(x)2.
1±1+cos(11π12)2
Step 4
Change the ± to + because secant is positive in the first quadrant.
11+cos(11π12)2
Step 5
Simplify 11+cos(11π12)2.
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Step 5.1
Simplify the numerator.
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Step 5.1.1
The exact value of cos(11π12) is -6+24.
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Step 5.1.1.1
Apply the reference angle by finding the angle with equivalent trig values in the first quadrant. Make the expression negative because cosine is negative in the second quadrant.
11-cos(π12)2
Step 5.1.1.2
Split π12 into two angles where the values of the six trigonometric functions are known.
11-cos(π4-π6)2
Step 5.1.1.3
Apply the difference of angles identity cos(x-y)=cos(x)cos(y)+sin(x)sin(y).
11-(cos(π4)cos(π6)+sin(π4)sin(π6))2
Step 5.1.1.4
The exact value of cos(π4) is 22.
11-(22cos(π6)+sin(π4)sin(π6))2
Step 5.1.1.5
The exact value of cos(π6) is 32.
11-(2232+sin(π4)sin(π6))2
Step 5.1.1.6
The exact value of sin(π4) is 22.
11-(2232+22sin(π6))2
Step 5.1.1.7
The exact value of sin(π6) is 12.
11-(2232+2212)2
Step 5.1.1.8
Simplify -(2232+2212).
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Step 5.1.1.8.1
Simplify each term.
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Step 5.1.1.8.1.1
Multiply 2232.
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Step 5.1.1.8.1.1.1
Multiply 22 by 32.
11-(2322+2212)2
Step 5.1.1.8.1.1.2
Combine using the product rule for radicals.
11-(2322+2212)2
Step 5.1.1.8.1.1.3
Multiply 2 by 3.
11-(622+2212)2
Step 5.1.1.8.1.1.4
Multiply 2 by 2.
11-(64+2212)2
11-(64+2212)2
Step 5.1.1.8.1.2
Multiply 2212.
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Step 5.1.1.8.1.2.1
Multiply 22 by 12.
11-(64+222)2
Step 5.1.1.8.1.2.2
Multiply 2 by 2.
11-(64+24)2
11-(64+24)2
11-(64+24)2
Step 5.1.1.8.2
Combine the numerators over the common denominator.
11-6+242
11-6+242
11-6+242
Step 5.1.2
Write 1 as a fraction with a common denominator.
144-6+242
Step 5.1.3
Combine the numerators over the common denominator.
14-(6+2)42
Step 5.1.4
Apply the distributive property.
14-6-242
14-6-242
Step 5.2
Simplify the denominator.
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Step 5.2.1
Multiply the numerator by the reciprocal of the denominator.
14-6-2412
Step 5.2.2
Multiply 4-6-2412.
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Step 5.2.2.1
Multiply 4-6-24 by 12.
14-6-242
Step 5.2.2.2
Multiply 4 by 2.
14-6-28
14-6-28
Step 5.2.3
Rewrite 4-6-28 as 4-6-28.
14-6-28
Step 5.2.4
Simplify the denominator.
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Step 5.2.4.1
Rewrite 8 as 222.
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Step 5.2.4.1.1
Factor 4 out of 8.
14-6-24(2)
Step 5.2.4.1.2
Rewrite 4 as 22.
14-6-2222
14-6-2222
Step 5.2.4.2
Pull terms out from under the radical.
14-6-222
14-6-222
Step 5.2.5
Multiply 4-6-222 by 22.
14-6-22222
Step 5.2.6
Combine and simplify the denominator.
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Step 5.2.6.1
Multiply 4-6-222 by 22.
14-6-22222
Step 5.2.6.2
Move 2.
14-6-222(22)
Step 5.2.6.3
Raise 2 to the power of 1.
14-6-222(212)
Step 5.2.6.4
Raise 2 to the power of 1.
14-6-222(2121)
Step 5.2.6.5
Use the power rule aman=am+n to combine exponents.
14-6-22221+1
Step 5.2.6.6
Add 1 and 1.
14-6-22222
Step 5.2.6.7
Rewrite 22 as 2.
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Step 5.2.6.7.1
Use nax=axn to rewrite 2 as 212.
14-6-222(212)2
Step 5.2.6.7.2
Apply the power rule and multiply exponents, (am)n=amn.
14-6-2222122
Step 5.2.6.7.3
Combine 12 and 2.
14-6-222222
Step 5.2.6.7.4
Cancel the common factor of 2.
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Step 5.2.6.7.4.1
Cancel the common factor.
14-6-222222
Step 5.2.6.7.4.2
Rewrite the expression.
14-6-22221
14-6-22221
Step 5.2.6.7.5
Evaluate the exponent.
14-6-2222
14-6-2222
14-6-2222
Step 5.2.7
Combine using the product rule for radicals.
1(4-6-2)222
Step 5.2.8
Multiply 2 by 2.
1(4-6-2)24
1(4-6-2)24
Step 5.3
Multiply the numerator by the reciprocal of the denominator.
14(4-6-2)2
Step 5.4
Multiply 4(4-6-2)2 by 1.
4(4-6-2)2
Step 5.5
Multiply 4(4-6-2)2 by (4-6-2)2(4-6-2)2.
4(4-6-2)2(4-6-2)2(4-6-2)2
Step 5.6
Combine and simplify the denominator.
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Step 5.6.1
Multiply 4(4-6-2)2 by (4-6-2)2(4-6-2)2.
4(4-6-2)2(4-6-2)2(4-6-2)2
Step 5.6.2
Raise (4-6-2)2 to the power of 1.
4(4-6-2)2(4-6-2)21(4-6-2)2
Step 5.6.3
Raise (4-6-2)2 to the power of 1.
4(4-6-2)2(4-6-2)21(4-6-2)21
Step 5.6.4
Use the power rule aman=am+n to combine exponents.
4(4-6-2)2(4-6-2)21+1
Step 5.6.5
Add 1 and 1.
4(4-6-2)2(4-6-2)22
Step 5.6.6
Rewrite (4-6-2)22 as (4-6-2)2.
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Step 5.6.6.1
Use nax=axn to rewrite (4-6-2)2 as ((4-6-2)2)12.
4(4-6-2)2(((4-6-2)2)12)2
Step 5.6.6.2
Apply the power rule and multiply exponents, (am)n=amn.
4(4-6-2)2((4-6-2)2)122
Step 5.6.6.3
Combine 12 and 2.
4(4-6-2)2((4-6-2)2)22
Step 5.6.6.4
Cancel the common factor of 2.
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Step 5.6.6.4.1
Cancel the common factor.
4(4-6-2)2((4-6-2)2)22
Step 5.6.6.4.2
Rewrite the expression.
4(4-6-2)2((4-6-2)2)1
4(4-6-2)2((4-6-2)2)1
Step 5.6.6.5
Simplify.
4(4-6-2)2(4-6-2)2
4(4-6-2)2(4-6-2)2
4(4-6-2)2(4-6-2)2
Step 5.7
Cancel the common factor of 4 and 2.
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Step 5.7.1
Factor 2 out of 4(4-6-2)2.
2(2(4-6-2)2)(4-6-2)2
Step 5.7.2
Cancel the common factors.
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Step 5.7.2.1
Factor 2 out of (4-6-2)2.
2(2(4-6-2)2)2(4-6-2)
Step 5.7.2.2
Cancel the common factor.
2(2(4-6-2)2)2(4-6-2)
Step 5.7.2.3
Rewrite the expression.
2(4-6-2)24-6-2
2(4-6-2)24-6-2
2(4-6-2)24-6-2
Step 5.8
Simplify the numerator.
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Step 5.8.1
Apply the distributive property.
242-62-224-6-2
Step 5.8.2
Simplify.
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Step 5.8.2.1
Multiply 4 by 2.
28-62-224-6-2
Step 5.8.2.2
Multiply 2 by -1.
28-26-224-6-2
Step 5.8.2.3
Multiply 2 by -1.
28-26-224-6-2
28-26-224-6-2
28-26-224-6-2
Step 5.9
Multiply 28-26-224-6-2 by 4-6+24-6+2.
28-26-224-6-24-6+24-6+2
Step 5.10
Multiply 28-26-224-6-2 by 4-6+24-6+2.
28-26-22(4-6+2)(4-6-2)(4-6+2)
Step 5.11
Expand the denominator using the FOIL method.
28-26-22(4-6+2)16-46+42-46+62-12-42+12-22
Step 5.12
Simplify.
28-26-22(4-6+2)20-86
Step 5.13
Cancel the common factor of 2 and 20-86.
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Step 5.13.1
Factor 2 out of 28-26-22(4-6+2).
2(8-26-22(4-6+2))20-86
Step 5.13.2
Cancel the common factors.
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Step 5.13.2.1
Factor 2 out of 20.
2(8-26-22(4-6+2))210-86
Step 5.13.2.2
Factor 2 out of -86.
2(8-26-22(4-6+2))210+2(-46)
Step 5.13.2.3
Factor 2 out of 2(10)+2(-46).
2(8-26-22(4-6+2))2(10-46)
Step 5.13.2.4
Cancel the common factor.
2(8-26-22(4-6+2))2(10-46)
Step 5.13.2.5
Rewrite the expression.
8-26-22(4-6+2)10-46
8-26-22(4-6+2)10-46
8-26-22(4-6+2)10-46
Step 5.14
Multiply 8-26-22(4-6+2)10-46 by 10+4610+46.
8-26-22(4-6+2)10-4610+4610+46
Step 5.15
Multiply 8-26-22(4-6+2)10-46 by 10+4610+46.
8-26-22(4-6+2)(10+46)(10-46)(10+46)
Step 5.16
Expand the denominator using the FOIL method.
8-26-22(4-6+2)(10+46)100+406-406-1662
Step 5.17
Simplify.
8-26-22(4-6+2)(10+46)4
Step 5.18
Cancel the common factor of 10+46 and 4.
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Step 5.18.1
Factor 2 out of 8-26-22(4-6+2)(10+46).
2(8-26-22(4-6+2)(5+26))4
Step 5.18.2
Cancel the common factors.
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Step 5.18.2.1
Factor 2 out of 4.
2(8-26-22(4-6+2)(5+26))2(2)
Step 5.18.2.2
Cancel the common factor.
2(8-26-22(4-6+2)(5+26))22
Step 5.18.2.3
Rewrite the expression.
8-26-22(4-6+2)(5+26)2
8-26-22(4-6+2)(5+26)2
8-26-22(4-6+2)(5+26)2
Step 5.19
Group 5+26 and 8-26-22 together.
(5+26)8-26-22(4-6+2)2
Step 5.20
Apply the distributive property.
(58-26-22+268-26-22)(4-6+2)2
Step 5.21
Combine using the product rule for radicals.
(58-26-22+2(8-26-22)6)(4-6+2)2
Step 5.22
Move 6 to the left of 8-26-22.
(58-26-22+26(8-26-22))(4-6+2)2
(58-26-22+26(8-26-22))(4-6+2)2
Step 6
The result can be shown in multiple forms.
Exact Form:
(58-26-22+26(8-26-22))(4-6+2)2
Decimal Form:
7.66129757
 [x2  12  π  xdx ]