Evaluate Cos 45o Cos 30o - Sin 45o Sin 30o leav... - WAEC Mathematics 2003 Question
Evaluate Cos 45o Cos 30o - Sin 45o Sin 30o leaving the answer in surd form
A
\(\frac{\sqrt{2}-1}{2}\)
B
\(\frac{\sqrt{3}-\sqrt{2}}{4}\)
C
\(\frac{\sqrt{6}-\sqrt{2}}{2}\)
D
\(\frac{\sqrt{6}-\sqrt{2}}{4}\)
correct option: d
\(cos45^o \times cos30^o - sin45^o \times sin30^o\
\frac{1}{\sqrt{2}}\times \frac{\sqrt{3}}{2} - \frac{1}{\sqrt{2}}\times \frac{1}{2}\
\frac{\sqrt{3}}{2\sqrt{2}}-\frac{1}{2\sqrt{2}}; = \frac{\sqrt{3}-1}{2\sqrt{2}}=\frac{\sqrt{6}-\sqrt{2}}{4}\)
\frac{1}{\sqrt{2}}\times \frac{\sqrt{3}}{2} - \frac{1}{\sqrt{2}}\times \frac{1}{2}\
\frac{\sqrt{3}}{2\sqrt{2}}-\frac{1}{2\sqrt{2}}; = \frac{\sqrt{3}-1}{2\sqrt{2}}=\frac{\sqrt{6}-\sqrt{2}}{4}\)
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