$4.$ Company A uses no debt, its beta is $1\mathrm{.}25$ and its tax rate is $35\%.$ However, the company is changing its capital structure to $25\%$ debt and $75\%$ equity. If the risk$-$free rate is $3\mathrm{.}5\%$ and the expected return on the market is $8\mathrm{.}5\%,$ by how much would the capital structure shift increase the firm's cost of equity?

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