- #1
odolwa99
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My answer is almost correct, except for the negative sign. Can anyone help?
Many thanks.
Q. Without using a calculator, show that [itex]\sin10^{\circ}+\sin80^{\circ}=\sqrt{2}\cos35^o[/itex]
[itex]2\sin(\frac{90}{2})\cos(\frac{-70}{2})[/itex]
[itex]-2\sin45\cos35[/itex]
[itex]-2(\frac{1}{\sqrt{2}})\cos35[/itex]
[itex]\frac{-2}{\sqrt{2}}\cos35[/itex]
[itex]\frac{-2\sqrt{2}}{2}\cos35[/itex]
[itex]-\sqrt{2}\cos35[/itex]
Many thanks.
Homework Statement
Q. Without using a calculator, show that [itex]\sin10^{\circ}+\sin80^{\circ}=\sqrt{2}\cos35^o[/itex]
Homework Equations
The Attempt at a Solution
[itex]2\sin(\frac{90}{2})\cos(\frac{-70}{2})[/itex]
[itex]-2\sin45\cos35[/itex]
[itex]-2(\frac{1}{\sqrt{2}})\cos35[/itex]
[itex]\frac{-2}{\sqrt{2}}\cos35[/itex]
[itex]\frac{-2\sqrt{2}}{2}\cos35[/itex]
[itex]-\sqrt{2}\cos35[/itex]