 | Thomas Kimber - 1874 - 352 σελίδες
...19ÍA. — Afternoon, 3 to 6. — Trigonometry and Conies.) 11. Define the cosine of an angle. Show that cos. (A — B) == cos. A cos. В + sin. A sin. B. Find the cosine of 15°. 12. Show that in any triangle the sides are proportional to the sines of the... | |
 | Thomas Kimber - 1880 - 176 σελίδες
...the hyperbola, and show that these are equidistant from the point of contact. 13. Prove geometrically that cos. (A — B) = cos. A . cos В + sin. A . sin. B, supposing A and В to be both angles in the second quadrant. 14. Given the area of a triangle and two... | |
 | United States. Congress. Senate - 1880 - 1304 σελίδες
...2. Trace the changes in the sign and magnitude of the fraction ' ' as 0 varies ( fl from 0 to ^. 3. Prove that cos (A + B) = cos A cos В — sin A sin B. Apply this formula to find the value of cos 135°. 4. Solve the equations — (я) Таи -П — 3... | |
 | John Bascombe Lock - 1896 - 244 σελίδες
...deduce the formula tan (180° + A) = tan A. 81. Compute by means of tables the value of a««"". 82. Prove that cos (A + B) = cos A cos В - sin A sin B, and deduce the expression for sin (A + B). 83. Establish the identities : (1) 1 + coaA -sin Л = V2(l... | |
 | John Bascombe Lock - 1896 - 242 σελίδες
...77 are very nearly the same. 76. To prove that sin (A + B) = sin A • cos В + cos A • sin B, and that cos (A + B) = cos A . cos В — sin A • sin B. Let XOE be the angle A, and EOF the angle B, then XOF is the angle (А + Б). In OF, the line which... | |
 | 1900 - 650 σελίδες
...ten marks beiny allowed for each. Mr. SULLIVAN, Head Inspector. Mr. CROMIE, District Inspector. 1. Prove that — cos (A - B) = cos A . cos В + sin A . sin В where A and В are each less than a right angle. 2. Find the limits between which A must lie if... | |
 | W. G. Borchardt, A. D. Perrott - 1928 - 492 σελίδες
...(180° - B) sin A = — sin B sin A, and projection of OQ on OX = sum of projections of ON and NQ, .'. cos (A + B) = cos A cos В — sin A sin B. If OY is perpendicular to OX, then projection of OQ on OY = OQ sin (A + B) = sin (A + B), projection of... | |
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Then show that cos (A + B) = cos A cos В — sin A sin B. 