https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:radians/v/radian-and-degree-conversion-practice 2021-06-30T17:32:35Z Radians & degrees Sal discusses the general approach to converting between radians and degrees and vice versa. Sal Khan video https://cdn.kastatic.org/googleusercontent/yAyM46fWGfQtHnhxpflFQxL7zcSuYJcn2U6TlkNW7glFoZbraXInBBsW-aA-k_raj_-JKWHI5PtUDWLcz5T1HEWAEA Radians & degrees Sal discusses the general approach to converting between radians and degrees and vice versa. https://cdn.kastatic.org/ka-youtube-converted/z8vj8tUCkxY.mp4/z8vj8tUCkxY.mp4 432 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:radians/v/we-converting-degrees-to-radians 2023-04-07T21:01:16.754798936Z Degrees to radians To convert from degrees to radians, multiply the number of degrees by π/180. This will give you the measurement in radians. If you have an angle that's 90 degrees, and you want to know what it is in radians, you multiply 90 by π/180. This gives you π/2. Sal Khan video https://cdn.kastatic.org/googleusercontent/pdtYhwt9PVlIF0D3yoW6P1KUuq4LIl1nNARsaXJB002V4y1whSc2jwtQnd1UObJn9wFfucuq5tWFwpYVS-8d6FhgJA Degrees to radians To convert from degrees to radians, multiply the number of degrees by π/180. This will give you the measurement in radians. If you have an angle that's 90 degrees, and you want to know what it is in radians, you multiply 90 by π/180. This gives you π/2. https://cdn.kastatic.org/ka-youtube-converted/O3jvUZ8wvZs.mp4/O3jvUZ8wvZs.mp4 422 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:radians/v/we-converting-radians-to-degrees 2023-05-02T21:08:26.186654054Z Radians to degrees To change from radians to degrees, you need to multiply the number of radians by 180/π. This number will help you switch between the two units. For example, if you multiply π/2 radians by 180/π, you will get 90 degrees. Sal Khan video https://cdn.kastatic.org/googleusercontent/BbYLiHp6ruJzV-OilzTvOOlaznPBxkii-I8uXWp6WqEqGcnVOnvvn7bbH9pexOUdvMBLOEhA48ZJq7AdyJwZ4TxY Radians to degrees To change from radians to degrees, you need to multiply the number of radians by 180/π. This number will help you switch between the two units. For example, if you multiply π/2 radians by 180/π, you will get 90 degrees. https://cdn.kastatic.org/ka-youtube-converted/z0-1gBy1ykE.mp4/z0-1gBy1ykE.mp4 200 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:unit-circle/v/unit-circle-definition-of-trig-functions-1 2021-06-30T17:32:39Z Unit circle Learn how to use the unit circle to define sine, cosine, and tangent for all real numbers. Sal Khan video https://cdn.kastatic.org/googleusercontent/4va3CHgzmCX8w1NMhs0LlyYxLMiXHDwZ-dDm8quQ0X5OKdz1Yj1KGmmUatzGzQcx5s4jzRHet0bYdh0NK-KNxB3iTw Unit circle Learn how to use the unit circle to define sine, cosine, and tangent for all real numbers. https://cdn.kastatic.org/ka-youtube-converted/1m9p9iubMLU.mp4/1m9p9iubMLU.mp4 544 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:unit-circle/v/matching-ratios-trig-functions 2021-06-30T17:32:35Z The trig functions & right triangle trig ratios Sal shows how, for acute angles, the two different definitions of the trigonometric values (SOH CAH TOA and the unit circle definition) result in the same values. Sal Khan video https://cdn.kastatic.org/googleusercontent/c0UdQAIw0Z9Y4urOKTHbmOHKFTJHkq7hOgH3dDSYlUf2TnGutCehCIcgi4p5iBxnlOEdinR2IhzIwUgqGyl3NnBy The trig functions & right triangle trig ratios Sal shows how, for acute angles, the two different definitions of the trigonometric values (SOH CAH TOA and the unit circle definition) result in the same values. https://cdn.kastatic.org/ka-youtube-converted/WffVdYETdng.mp4/WffVdYETdng.mp4 417 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:special-angles/v/solving-triangle-unit-circle 2021-06-30T17:32:34Z Trig values of π/4 Sal finds the trigonometric values of π/4 using the unit-circle definition. Sal Khan video https://cdn.kastatic.org/googleusercontent/KR3yVel6ABULTaZmJ3T74ecv_lm4WfLV40v28QuXhprHX--TwL20KNi2dDhmMqdpBDQSOSUYfmOrcu8AasFsTJKmpg Trig values of π/4 Sal finds the trigonometric values of π/4 using the unit-circle definition. https://cdn.kastatic.org/ka-youtube-converted/KoYZErFpZ5Q.mp4/KoYZErFpZ5Q.mp4 474 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:trig-graphs/v/we-graph-domain-and-range-of-sine-function 2021-06-30T17:32:37Z Graph of y=sin(x) The graph of y=sin(x) is like a wave that forever oscillates between -1 and 1, in a shape that repeats itself every 2π units. Specifically, this means that the domain of sin(x) is all real numbers, and the range is [-1,1]. See how we find the graph of y=sin(x) using the ​unit-circle definition of sin(x). Sal Khan video https://cdn.kastatic.org/googleusercontent/wcQ2syzE8sXK5vEFyjUv9Txzin7B20FsTpIWG7-pVpwzGEXP8P_CV9vbbCmrTCt7DcH99QZ92uaLVy6Xr5B1MOcAcg Graph of y=sin(x) The graph of y=sin(x) is like a wave that forever oscillates between -1 and 1, in a shape that repeats itself every 2π units. Specifically, this means that the domain of sin(x) is all real numbers, and the range is [-1,1]. See how we find the graph of y=sin(x) using the ​unit-circle definition of sin(x). https://cdn.kastatic.org/ka-youtube-converted/sjUhr0HkLUg.mp4/sjUhr0HkLUg.mp4 562 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:trig-id/v/trig-angle-rotations 2021-05-05T14:53:17Z Sine & cosine identities: periodicity Sal finds trigonometric identities for sine and cosine by considering angle rotations on the unit circle. Sal Khan video https://cdn.kastatic.org/googleusercontent/8R9ptji40BAkC_jOzCeGm6Fcnoe-QabEA_HoLfqCyjc0pTzHeTD_nCa92YdE8v1RV1B176jw6mZzX53nxrTkLjqx Sine & cosine identities: periodicity Sal finds trigonometric identities for sine and cosine by considering angle rotations on the unit circle. https://cdn.kastatic.org/ka-youtube-converted/h-TPSylHrvE.mp4/h-TPSylHrvE.mp4 373 Trigonometric Functions https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:trig/x2ec2f6f830c9fb89:trig-graphs/v/tangent-graph 2021-06-30T17:32:37Z Graph of y=tan(x) Sal draws the graph of the tangent function based on the unit circle definition of the function. Sal Khan video https://cdn.kastatic.org/googleusercontent/EBg8q9NQjbOdgFab6-psusfvsJ4q20mi-iWROa_qeSuMLeIiZsG4JXveE4zx0eHgPVlCOrGzOrUgD5HbkkBQUzVPNQ Graph of y=tan(x) Sal draws the graph of the tangent function based on the unit circle definition of the function. https://cdn.kastatic.org/ka-youtube-converted/FK6-tZ5D7xM.mp4/FK6-tZ5D7xM.mp4 612 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:angle-addition/v/trigonometry-identity-review-fun 2021-05-05T14:53:24Z Trig angle addition identities Sal reviews 6 related trigonometric angle addition identities: sin(a+b), sin(a-c), cos(a+b), cos(a-b), cos(2a), and sin(2a). Sal Khan video https://cdn.kastatic.org/googleusercontent/q779WlSevH6c0FCkG6uJcgjnP-3oXG6igoQNkUMmaUC_iYs2ef5ZtpHgGVMziteKMOmz7gjlpqZzF16rq8z2hxo Trig angle addition identities Sal reviews 6 related trigonometric angle addition identities: sin(a+b), sin(a-c), cos(a+b), cos(a-b), cos(2a), and sin(2a). https://cdn.kastatic.org/ka-youtube-converted/a70-dYvDJZY.mp4/a70-dYvDJZY.mp4 667 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:angle-addition/v/cosine-addition-identity-example 2021-05-05T14:53:16Z Using the cosine angle addition identity Sal evaluates the cosine of the sum of 60° and another angle whose right triangle is given. To do this, he must use the cosine angle addition formula. Sal Khan video https://cdn.kastatic.org/googleusercontent/OirHRBIT_x63S6CU99h-fPyl2X_hDf7HZAM9tO9PaiIgSfaay7XSpcxQW-xYIn2jLljKXyz0qnd0vzmSZ1J7HWFVGA Using the cosine angle addition identity Sal evaluates the cosine of the sum of 60° and another angle whose right triangle is given. To do this, he must use the cosine angle addition formula. https://cdn.kastatic.org/ka-youtube-converted/h0SNEO25vIw.mp4/h0SNEO25vIw.mp4 314 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:trig-id/v/trigonometry-unit-circle-symmetry 2021-05-05T14:53:18Z Sine & cosine identities: symmetry Sal finds several trigonometric identities for sine and cosine by considering horizontal and vertical symmetries of the unit circle. Sal Khan video https://cdn.kastatic.org/googleusercontent/hX3WT_E5jPWwlXRobWPxGJq4OYInNRchN78MjUoOWRLZ23yRk-N961XQLvHLPtx2NymQIUgGR3tt9gH8UrMZy3qZQA Sine & cosine identities: symmetry Sal finds several trigonometric identities for sine and cosine by considering horizontal and vertical symmetries of the unit circle. https://cdn.kastatic.org/ka-youtube-converted/tzQ7arA917E.mp4/tzQ7arA917E.mp4 478 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:trig-id/v/tan-symmetries-unit-circle 2021-05-05T14:53:19Z Tangent identities: symmetry Sal finds several trigonometric identities for tangent by considering horizontal and vertical symmetries of the unit circle. Sal Khan video https://cdn.kastatic.org/googleusercontent/aJtG2MsWehGm34mtnN3fAUg8BPOp0PGeiziyIRmQaK4Ebf6XpWlPiE20cqN1fkmi3chWHluIhcbuH_MBKkj_7IrQ Tangent identities: symmetry Sal finds several trigonometric identities for tangent by considering horizontal and vertical symmetries of the unit circle. https://cdn.kastatic.org/ka-youtube-converted/k_wJsio68D4.mp4/k_wJsio68D4.mp4 435 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:trig-id/v/tan-periodicity 2021-05-05T14:53:17Z Tangent identities: periodicity Sal solves a problem by considering the periodicity of the tangent function. Sal Khan video https://cdn.kastatic.org/googleusercontent/5syk7G_FmY-hYDAt88Z5TlQSkzxwSrnumrebAKIXOM2UegBtXO_8qFabPmW7WxnYvRCzlPDcYN8JgVexBKAcx5c Tangent identities: periodicity Sal solves a problem by considering the periodicity of the tangent function. https://cdn.kastatic.org/ka-youtube-converted/C3HFAyigqoY.mp4/C3HFAyigqoY.mp4 242 Trigonometric Functions https://www.khanacademy.org/math/precalculus/x9e81a4f98389efdf:trig/x9e81a4f98389efdf:angle-addition/v/double-angle-formula-for-cosine-example-c 2021-05-05T14:53:17Z Using the cosine double-angle identity The cosine double angle formula tells us that cos(2θ) is always equal to cos²θ-sin²θ. For example, cos(60) is equal to cos²(30)-sin²(30). We can use this identity to rewrite expressions or solve problems. See some examples in this video. Sal Khan video https://cdn.kastatic.org/googleusercontent/152bMm2bPz9qxWTKf3kD6x5ejlJKR-tLzP7uUkfHeN7OOT9OJRqTPVW19HlJJNGXMZ8DK5MLDrNHrPU91DCpPMs Using the cosine double-angle identity The cosine double angle formula tells us that cos(2θ) is always equal to cos²θ-sin²θ. For example, cos(60) is equal to cos²(30)-sin²(30). We can use this identity to rewrite expressions or solve problems. See some examples in this video. https://cdn.kastatic.org/ka-youtube-converted/D_smr0GBPvA.mp4/D_smr0GBPvA.mp4 208 Trigonometric Functions https://www.khanacademy.org/math/trigonometry/trig-equations-and-identities/challenge-trig-problems/v/cosine-angle-addition-2 2020-07-26T05:38:46Z Trig challenge problem: cosine of angle-sum Sal is given cos(θ) and cos(φ) and he finds cos(θ+φ). To do that, he must first find sin(θ) and sin(φ) using the Pythagorean identity. Sal Khan video https://cdn.kastatic.org/googleusercontent/gt-svavuQuwt7iAWDnZV6UyGzNNMvbw25U-cxH5Gi0mS_GlRFN35JIfd91yrzf9VquOEKamykMfIkpy0E3aQpVrckA Trig challenge problem: cosine of angle-sum Sal is given cos(θ) and cos(φ) and he finds cos(θ+φ). To do that, he must first find sin(θ) and sin(φ) using the Pythagorean identity. https://cdn.kastatic.org/ka-youtube-converted/XGpEHj43kcc.mp4/XGpEHj43kcc.mp4 434 Trigonometric Functions https://www.khanacademy.org/math/ka-revision-class-11-math/x64e5efbb29d87707:week-1-revision-ncert-class-11-math/x64e5efbb29d87707:trigonometric-functions-revision-ncert-class-11-math/e/revision-trigonometric-functions-ncert-class-11-math 2026-04-07T22:23:57.656416987Z Revision Trigonometric Functions Practice Problems for revision of Trigonometric Functions. Satya Swaroop exercise